2. PET - PreformManufacturing & Blowing

8/13/2019 2. PET - PreformManufacturing & Blowing

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PET BOTTLE QUALITY TOOL

Page 1PQT: PET Preform Manufacturing FINAL: SEPTEMBER 2002

PreformManufacturing


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Packaging Quality Tool

Preform Manufacturing

Guiding

PrinciplesUnderstand

Raw Materials

Process

Supplier

Approval

Concerns 1) Resin morphology- Degree of Crystallinity

2) Hydrolytic Degradation:

- Drying of PET

- Moisture Content

3) Intrinsic Viscosity(IV):

- IV reduction

Preform/PET BottleManufacturing

RawMaterials

1) Starting materials for PET

are Paraxylene & Ethylene

2) Starting materials form two

intermediates (EthyleneGlycol & Terephthalic Acid)

which react to form a

monomer

3) Monomer is polycondensed

to form a long polymer

called Polyethylene

Terephthalate (PET)

Capability to manufacture

PET bottles that

meet PBI specifications

1) Resin Storage

2) PET Resin Drying

3) Injection molding of preforms

4) Preform in plant testing

5) Preform storage & distribution

6) Preform/PET bottle receipt

and inspection

7) Preform storage

8) Preform Pre-heating

9) PET Bottle Blowing

10) PET Bottle Storage

1) Resin to be dried to < 50ppm2) Thermal degradation (heat abuse)

will lead to: a) Reduction in I.V. &

b) Acetaldehyde (AA) generation

3) Maximum drop of 0.02 dl/gr. allowed

4) Preforms must be purchased from

PBI qualified suppliers

5) Preforms should be conditioned

over night prior to blowing

6) PET bottles stored in a dry

environment

Maintain Quality of the

Package after Receipt

at the Beverage Plant

1) PET Bottle receipt, inspection

and storage

2) PET bottle rinsing/washing

3) Bottle filling

4) Filled PET bottle storage

1) Receiving and inspectionCOC/COA ; minimum

incoming inspection

2) Base bursting

QualityAssurance

BeveragePlant

Use Only PET bottles

that Meet PBI

Specifications

1) PET bottles outsidespecifications

2) Stress-cracking

3) CO2 loss

PET bottle specifications

Parameter

Bottle Appearance

Dimensions

Bottle HeightMajor Diameters

Bottle Weight

Fill Height Capacity

Perpendicularity

Wall Thickness

Material Distribution

Internal Pressure

PBI PET bottle


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(2) Understand the suppliers capability to

consistently supply PET bottles that meet

PBI specifications

Guiding Principle



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Agenda

Preform Manufacturing Overview

Unit operations

Acetaldehyde (AA) Preform in-plant testing


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Typical Description of a Preform

Neck Support

Ring

Gate

Body

Neck Finish

Locking Ring Neck Finish does not

change after injectionmolding process

Preform body is stretched inblowing process

Gate area does not changeafter injection molding

process



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Bottle Finish Dimension Letters

The standard neck finishes are:- BPF: British Plastic Federation

- PCO: Plastic Closure Only

www.threadspecs.com


Band


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How are Preforms Made and Their Critical Parameters

PET Resin Injection Molding

of Preforms

Injection Molding

of Preforms PreformPreform

Preform

Handling &

Storage

Preform

Handling &

Storage

PET Resin

Receipt

&

Storage

PET Resin

Receipt

&

Storage

Moisture: 14ppm


I.V.: 0.80-0.84+/-0.02

dl/gr.

Acetaldehyde:< 1 ppm


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Receipt and Storage of PET Resin

Process: PET resins are shipped in corrugated boxes, bulk tank trucks

and bulk rail cars to the preform manufacturing facility

Resins are stored in silos with a capacity of 75 tonnes(approx.)

Silos are typically made of aluminum and/or stainless steel


Dried at -40C dewpoint and 180C (356F)

PET ResinPET Resin Injection Molding

of Preforms

Injection Molding

of PreformsPreform

PreformPreform

Handling &

Storage

Preform

Handling &

Storage

PET Resin

Receipt& Storage

PET Resin

Receipt& Storage

PET ResinDrying

PET Resin

Drying


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Receipt and Storage of PET Resin

Concern:

Bulk tankers should be cleaned prior to loading andtransportation

Good manufacturing practices should be followed in thetransfer of resin to the silos. Avoid soil contamination, i.e.stones being pick up in the transfer process

Stainless steel flexing should be used in the resin transfer

process. Avoid using rubber hosing as it wears quickly



PET ResinPET Resin Injection Molding

of Preforms

Injection Molding

of PreformsPreform

PreformPreform

Handling &

Storage

Preform

Handling &

Storage

PET Resin

Receipt& Storage

PET Resin

Receipt& Storage

PET ResinDrying

PET Resin

Drying


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Process:

Drying involves placing the PET polymer in a drier of between

0.5 and 4 metric tons capacity and blowing hot dry air throughit

It will typically take between 5 to 7 hours in the drier for thePET polymer to obtain the correct moisture level (< 50ppm) forprocessing

Carefully controlled drying is an essential requirement in orderto remove the moisture from the granules

Faulty drying cannot be reversed later on in the conversionprocess (PET resin to Preform)

The most common type of drying method used is the Heated

Air with Desiccant Dehumidifying process

How is Drying of PET Resin Accomplished?



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How is Drying of PET Resin Accomplished?

Concern:

The presence of a high moisture level in the resin will result in:

- Reduction of the Intrinsic Viscosity (I.V.) of the PETmaterial which will result in poor material distribution within

the PET bottle (accelerated CO2 loss with the finished

beverage).


PET ResinPET Resin Injection Moldingof Preforms

Injection Molding

of Preforms Preform

PreformPreform

Handling &Storage

Preform

Handling &

Storage

PET Resin

Receipt

& Storage

PET Resin

Receipt& Storage

PET ResinDrying

PET Resin

Drying



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Injection Molding of Preforms

Process:

PET resin is melted, compressed in an extruder and theninjected into water cooled cavities where it quickly solidifies toform a preform

Preforms are then stored and later transported to a PETblowing operation for stretch-blowing into PET bottles



PET ResinPET Resin Injection Moldingof Preforms

Injection Molding

of Preforms Preform

PreformPreform

Handling &Storage

Preform

Handling &

Storage

PET Resin

Receipt

& Storage

PET Resin

Receipt& Storage

PET ResinDrying

PET Resin

Drying


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PET ResinPET Resin

ScrewScrew

Barrel (~ 290C/554F to 320C/608F)Barrel (~ 290C/554F to 320C/608F)

PreformPreform

Gate sectionGate section

SprueSprue

Injection Molding of Preforms

ExtruderExtruderCavityCavity

Core PinCore Pin



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Concern:

Minimize resin degradation(thermal) which will result in:a) I.V. reduction (0.02dl/gr. Max. allowed), andb) high acetaldehyde

Preform clarity issues due to poor cooling of the preforms

Injection Molding of PreformsPET ResinPET Resin

ScrewScrew

Barrel (~ 290C/554F to 320C/608F)Barrel (~ 290C/554F to 320C/608F)

PreformPreform

Gate sectionGate section

SprueSprue

CavityCavity

Core PinCore Pin



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Agenda



Unit operations



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What is Acetaldehyde (CH3CHO)?

Acetaldehyde (AA):

In its pure state Acetaldehyde (AA) has a sharp fruity sweetapple taint

The rate of formation of AA is dependent on the PET resinformula and drying efficiency

AA is only formed in significant quantities during the preforminjection molding process

At room temperature (20C/68F), Acetaldehyde is a

colorless vapor which is soluble in water Acetaldehyde (AA) is a product of thermochemical (high

temperature abuse) degradation



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What is Acetaldehyde (CH3CHO)?

Preform AA specification:

Average AA < 10ppm, no one cavity > 14ppm

The presence of a high concentration of AA wouldindicate;

Poor processing conditions which could also result in a largedrop in the resin I.V. value (when resin is converted to apreform)

In the injection molding equipment certain cavities will

consistently produce high AA values in preforms These cavities are called High (Hot) or critical cavities

In performing AA analysis, one of these criticalcavities should be sampled once a week per mold to

determine AA concentration


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Haze Defect type: Hazy preforms

Description: Appears with varyingamounts ofcrystallinity in the

preform sidewallCause: Resin not dried

properly prior to

processingConcern: Stress cracking of

the filled PET bottle

Concerns From Preform Production



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Concerns From Preform Production

Defect type: Short Shots

Description: Neck finish notcompleted

Cause: In-sufficient polymerwas packed duringthe injection fill time

Concern: Poor bottle/closureseal - High CO2 loss

Short Shots



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Agenda



Unit operations



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PET ResinInjection Molding

of Preforms

Preform

Preform

Handling &

Storage

PET Resin

Receipt

& Storage

PET Resin

Drying

Typical In-Plant Testing Regime at the Preform Supplier

Test: Frequency: Equipment:

Preform weight A full round/day/mold Weighing Balance

Preform wall thickness 5 Preforms/day/mold Magna-Mike, Panametrics

Finish dimension During mold change over Callipers, Profile projector

Visual inspection A full round/shift /mold Magnifying Glass

I.V. Critical cavity/week/mold as a minimum As per ASTM D-4603

Acetaldehyde (AA) Critical cavity/week/mold as a minimum Gas Chromatograph



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PQT: PET Preform Manufacturing FINAL: SEPTEMBER 2002


Preform Handling and Storage

Normally packed in polyethylene plastic bags

which are closed to the surrounding environment Polyethylene liner is used to prevent dust and dirt

contamination

Preforms should not be stored in direct sunlight Stored in a covered/closed warehouse with ideal

temperatures of between 5C/41F to 35C/ 95F

at Relative Humidity < 60% 12 months maximum for storage of preforms is

recommended (from date of preform manufacture)

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Preform Handling and Storage

Information that should accompany theshipment:

a) Name of Supplier/City/Countryb) Lot Identification:

c) Certificate of Compliance/Analysis (COC\COA)

Lot code

Neck finish type Shift Production date Color

Resin type

Preform quantity/boxes Preform weight Shipment date Injection machine/line


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What are the Key Take-Aways From This Module?

Under controlled drying and molding conditions theI.V. loss for dried PET resin conversion to a preform

shall be less than 0.02dl/gr. Preforms can be stored for up to 12 months in a

closed/covered environment warehouse with ideal

temperatures of between 5C/41F to 35C/95F atRelative Humidity < 60%

The rate of formation of AA is dependent on the PETresin formula and is formed only in significant

quantities during the preform injection moldingprocess

Preform Acetaldehyde specification:

Average AA < 10ppm, no one cavity > 14ppm


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PET BOTTLE QUALITY TOOL

Page 1PQT: PET Bottle Blowing Manufacturing FINAL: SEPTEMBER 2002

PET BottleBlowing


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Packaging Quality Tool

PET Bottle Blowing

Guiding

PrinciplesUnderstand

Raw Materials

Process

Supplier

Approval

Concerns1) Resin morphology

- Degree of Crystallinity

2) Hydrolytic Degradation:

- Drying of PET

- Moisture Content

3) Intrinsic Viscosity(IV):

- IV reduction

Preform/PET BottleManufacturing

RawMaterials

1) Starting materials for PET

are Paraxylene & Ethylene

2) Starting materials form two

intermediates (EthyleneGlycol & Terephthalic Acid)

which react to form a

monomer

3) Monomer is polycondensed

to form a long polymer

called Polyethylene

Terephthalate (PET)

Capability to manufacture

PET bottles that

meet PBI specifications

1) Resin Storage

2) PET Resin Drying

3) Injection molding of preforms

4) Preform in plant testing

5) Preform storage & distribution6) Preform/PET bottle receipt

and inspection

7) Preform storage

8) Preform Pre-heating

9) PET Bottle Blowing

10) PET Bottle Storage

1) Resin to be dried to < 50ppm

2) Thermal degradation (heat abuse)

will lead to: a) Reduction in I.V. &

b) Acetaldehyde (AA) generation

3) Maximum drop of 0.02 dl/gr. allowed

4) Preforms must be purchased from

PBI qualified suppliers

5) Preforms should be conditioned

over night prior to blowing

6) PET bottles stored in a dry

environment

Maintain Quality of the

Package after Receipt

at the Beverage Plant

1) PET Bottle receipt, inspection

and storage

2) PET bottle rinsing/washing

3) Bottle filling

4) Filled PET bottle storage

1) Receiving and inspection

COC/COA ; minimum

incoming inspection

2) Base bursting

QualityAssurance

BeveragePlant

Use Only PET bottles

that Meet PBI

Specifications

1) PET bottles outside

specifications

2) Stress-cracking

3) CO2 loss

PET bottle specifications

Parameter

Bottle Appearance

Dimensions

Bottle HeightMajor Diameters

Bottle Weight

Fill Height Capacity

Perpendicularity

Wall Thickness

Material Distribution

Internal Pressure

PBI PET bottle


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(2) Understand the suppliers capability to

consistently supply PET bottles that meet

PBI specifications

Guiding Principle

PET Bottle Blowing


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Agenda

PET Bottle Blowing

Best Practice recommendationsfor incoming preforms

Operational Practices Preform receipt and inspection

Preform storage

PET bottle stretch-blowmolding

PET bottle storage


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Best Practice Recommendations for Preforms

PET Bottle Blowing

Preforms are purchased only from approved

suppliers Bottle blower is responsible for approving the

preform supplier.

Preforms must meet PBI Preform specifications COC/COA requirements are met on new preforms

either:

By supplier providing COC/COA with every lot, or

By COA testing being performed at the PET blowingfacility for each lot of preforms delivered


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PET Bottle Process Overview

PREFORM

RECEIVING/

INSPECTION

PET BOTTLE

BLOWING

EMPTY PET

STORAGE

Process: Sampling

COC/COA

Incoming Tests

Preform conditioning

Preheating oven

Stretch-blowing

Concerns: Acetaldehyde

Intrinsic Viscosity

Visual Defects

Mixing preforms with

different I.V.s

Stretch rod and pre-

blow timing

PREFORM

STORAGE

Preform storage

Storage time/temp

Relative humidity

FIFO

BEVERAGE PLANT

Temperature

Humidity

Odor

FIFO

Empty PET

bottle storage

PET Bottle Blowing


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Obtain bill of lading

Verify truck cleanliness Verify the certificate of compliance/analysis

Check preform pallet labels for correct details

Receiving/Inspection

PREFORMS

PET Bottle Blowing


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COC (Certificate of Compliance)

Written documentation showing contract terms Preform specification requirements (include preform

drawing reference number & resin type)

COA (Certificate of Analysis) Data for critical parameters:

Appearance

Dimensions (include neck finish) Intrinsic Viscosity of a) PET resin and b) preform

Acetaldehyde

Weight

COC & COA Requirements

PET Bottle Blowing


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Certificate of Compliance /Analysis

Provided by preform

supplier Does not replace

inspection criteria forthe PET bottle facility

Analyses must be from

that preform lot

Certificate of

Compliance &Analysis

PET Bottle Blowing

Certificate of Compliance/Analysis for Preforms

Supplier/Distributor ___________________ Bill of Lading No. ___________________ Shipped To (PET Blowing Plant) ___________________Date Delivered: ___________________ Batch No.: ___________________ Resin Type: ___________________

Preform Drawing No.: ___________________

This is to certify that the preforms contained in this shipment meets andconforms to all requirements called for in PepsiCo Beverage Internationalsspecifications dated_____.

Furthermore, the preforms in the specified delivery have been analyzed and the datarecorded for the specific standards shown below.

Test Items Specification Test Result

Appearance Free of visual defect

Weight < 30 grs: +/- 0.3 grs> 30 grs: +/-0.4 grs

Neck FinishDimension

As shown in PBI approved drawing

a) Resin IntrinsicViscosity

b) Preform IntrinsicViscosity

0.80-0.84 +/- 0.02 dl/grMaximum IV drop of 0.02 dl/gr from the

initial resin I (as per ASTM#D4603)

Acetaldehyde Avg. < 10.0 ppm with no individual cavity inexcess of 14.

* Only official PepsiCo Beverages International test methods must be used.

Certified by:

on(Signature) (Date)

______________________________ of_______________________________


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T E S T I N G R E Q U I R E D

COC/COA

Incoming Preform Receiving Process

NO

COC/COA

Appearance

Weight

Appearance

Weight

Dimensions

Intrinsic Viscosity of

Preform

Acetaldehyde (AA)

PET Bottle Blowing

3 SAMPLES/LOT

10 SAMPLES/LOT


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Sample randomly 10 preforms per truck or trailer

delivery. Samples should be taken from the front,

end, and middle of truck.

Evaluate these samples for:

1. Appearance2. Dimensions (include neck finish)

3. Weight

4. Intrinsic viscosity5. Acetaldehyde (AA)

Recommended Sampling Plan with No COC/COA?

If results are out

of specification,then reject this lot

of incoming

preforms

A Lot is defined as a truckload (trailer) of preforms

PET Bottle Blowing


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Process Overview

PREFORM

RECEIVING/

INSPECTION

PET BOTTLE

BLOWING

BEVERAGE

PLANT

Process: Sampling

COC/COA

Incoming Tests


Preheating oven

Stretch-blowing


Intrinsic Viscosity

Visual Defects

PREFORM

STORAGE

Preform storage

Storage time/temp

Relative humidity


different I.V.s


blow timing

EMPTY PET

STORAGE

Temperature

Humidity

Odor

FIFO

Empty PET

bottle storage

PET Bottle Blowing


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Storage of Preforms at the Beverage Plant

PET Bottle Blowing

A First In, First Out principle should be applied in thecase of preform inventory

Preforms age during storage 12 months maximum

The degree of aging is dependent upon storagetemperature and relative humidity. Acceptable storage

conditions are: Storage temperature 5C/41F to 35C/95F

Relative Humidity < 60%

As the age of the preform changes so too might the pre-heating oven set up conditions prior to PET bottle blowing

Transit packaging containing preforms should not bestacked too high as preform necks can be damaged (oval)

UPDATED: MARCH 2003


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Process Overview

PREFORM

RECEIVING/

INSPECTION

PET BOTTLE

BLOWING

Process: Sampling

COC/COA

Incoming Tests


Preheating oven

Stretchblowing


Intrinsic Viscosity

Visual Defects


different I.V.s


blow timing

PREFORM

STORAGE

Preform storage

Storage time/temp

Relative humidity

BEVERAGE

PLANTEMPTY PET

STORAGE

Temperature

Humidity

Odor pickup

Empty PET

bottle storage

PET Bottle Blowing


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PET Stretch-Blowing Process

PreformPreform Stretch RodStretch Rod MoldMold

Preform is heated(~ 105C/221F)

Preform is blown into a PET bottle(~ 65C/149F)

PET bottle blowing occurs in four steps:

1) Preform conditioning, 2) Preform heating, 3) Mechanical axial stretching &

4) Radial stretching using compressed air

PET Bottle Blowing


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Step 1: Preform Conditioning

PET Bottle Blowing

Process:

Preforms are stored in a warm dry area (Blowing hall preferably) for aminimum of 24 hours prior to pre-heating and blowing.

This conditioning allows for the preforms to be of a more uniformtemperature profile when presented to the pre-heating oven

Concern:

Mixing preforms from different lots, different storage conditions (i.e.,

temperature), different resins, and preform age can result in thefollowing issues occurring with the blown PET bottle;

a) Crystallinity (Preforms too hot or cold)

PET bottle opaque in color

b) Pearlescence (Preforms too cold) Hazy effect throughout bottle

c) Poor material distribution

Cold or unevenly heated preforms

Difficult to adjust the blowing machine


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Step 2: Preform Heating

Process:

Pre-heating oven consists of 8 -10 heatingzones (infra-red lamps). Heat intensity inheating zones is adjustable to facilitatematerial distribution

Preform neck is protected from heat by

cooling shield

Concern:

Poor preform heating results in:1. Poor material distribution in PET bottle

2. Poor wall thickness in PET bottle

3. Pearlescence on PET bottle sidewall

Infra RedInfra Red

lampslamps

Neck shieldsNeck shields

PET Bottle Blowing


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Process:

Heated Preforms (110C/230F approx.) aretransferred to the blow-molding equipment.

Preforms are placed between two blow moldsection halves. Mold temperatures of 65-95C(149-203F) are typical.

Mold sections are closed and clamped.

Concern:

If mold temperatures are too high then excessive

shrinkage will occur, resulting in low fill heightcapacity issues in the PET bottle.

Any preforms that drop out of the transfer unit(between heating oven and stretch-blowingequipment) must be scrapped.

Step 3: Mechanical Axial Stretching

Preform(Heated)

Mold Closes

Around Preform

Mold

PET Bottle Blowing


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Process:

Stretch rod is introduced via the preform neck which

longitudinally stretches the preform to the bottom ofthe mold

Axial molecular orientation takes place during thisstretching process

Air is then introduced into the bottle to distribute thematerial radially (around circumference)

Concern:

Rate that the preform is stretched is critical to thelevel of orientation in the PET bottle

Timing of the stretch rod and air blow, are critical informing a good PET bottle (moving material to theright places)

Step 3: Mechanical Axial Stretching

Air starts to

inflate preform

Stretch rod

(Pushespreform

downwards)

PET Bottle Blowing


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Process:Occurs in 2 Stages:

1) Pre-Blow and 2) Main Blow:

Pre-Blow Typically 9 bar pressure

Radial orientation of molecules takesplace

Timing of pre-blow determines amount ofmaterial in base

Main Blow

Typically 40 Bar Pressure

Follows Pre-Blow

Gives the final definition to the bottleshape

Step 4: Radial Stretching Using Compressed Air

Air Air

Air drives preformsidewalls outwardsto the mold surface

PET Bottle Blowing

PET B l Bl i


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Concerns:

In-correct timing between the stretch rod

initial movement and the pre-blow stage willresult in poor material distribution within thePET bottle. (Material begins to move early inthe blowing process to the PET bottle

shoulder and base areas - Results inaccelerated CO2 loss in filled PET bottles.

Inadequate venting of the air from the mold

can result in flat sidewalls at the parting lines.Defect known as Panelling which leads tofoaming issues at the filler

Step 4: Radial Stretching - Main Concerns

PET Bottle Blowing

Air Air

Air drives preformsidewalls outwards

to the mold surface

PET B ttl Bl i


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What Happens to the Preform During PET Bottle Blowing?

Stretch Blow molding & Biaxial Orientation:

Preform is biaxially stretched during blow molding (circumferentially & axially)

This biaxial orientation impacts certain physical properties,i.e., Gas permeation through the sidewall is decreased

The degree of biaxial orientation is influenced by how fast the bottle isstretched (Axial direction) and blown circumferentially

PET Bottle Blowing

PET B ttl Bl i


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Typical Types of Defects Found in Stretch-Blowing

Strangled

Neck:Too much

material in

top shoulder

area of PET

bottle

Defect Type: Visual Aid: Cause: Filled PET issue Remedy:

Pre-blow

too late

Preformsover orunder-heated

Correct

pre-blowtiming

Correct heatshields(reflectors)

Pre-blowtoo fast

Insufficient

blowpressure

Correctpre-blow timing

Adjust airpressure higher

Underblown

Feet:

Base area

of the PETbottle is

not fully

formed

Accelerated

CO2 loss, andPET fillingissues(foaming).

PET bottlestability issues,acceleratedCO

2loss and

potentialstress-crackingproblems

Less fill heightcapacity

PET Bottle Blowing

PET B ttl Bl i


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Defect Type: Visual Aid: Cause: Filled PET issue: Remedy:

Typical Types of Defects Found in Stretch-Blowing

Crystallinity:Material

appears as

opaque or

milky white in

appearance

Preforms too hot

(Haze on outside) In-adequate

mold cooling

Pre-blowpressure high

Lower heating

power Check mold

cooling water

Adjust pre-blow pressure

Crystallinity

Off Center

Gate:Gate section is

not centered

correctly

Off Center Gate Pre-blow too fast

before stretchrod centers ongate

Preform slants

Correct pre-blow timing

Lower blowair pressure

Check mold& threadalignment

Potential stress-

cracking issues,and acceleratedCO2 loss

Poor material

distribution,accelerated CO2loss andpotential stress-cracking issues

PET Bottle Blowing


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Neck Finish Dims.

Stress Cracking

Top Load

Burst Test

Fill HeightCapacity

Sectional Weights

Visual Inspection

Drop Impact Test

Dimensions(Height, Diameters)

One sample/mold/shift (8 hours)

One sample /mold/week


One sample/mold/4 hours


One sample/mold/2 hours




Callipers, Micrometer

0.2% NAOH, Stop Watch

Top Loader (e.g. Instron)

AGR Model 073

Weighing Balance, Water DensityTables, Thermometer

Weighing Balance, Cutting Tool

Magnifying Glass

Concrete slab, Temperaturechambers

Callipers, Micrometer, Height Gauge

Test: Frequency: Equipment:

Typical PET Bottle In-Plant Testing Regime

PET Bottle Manufacture - Stretch-blowing

PET B ttl Bl i


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One Stage vs. Two Stage Process

Two Stage One Stage

PET Bottle Blowing

PET B ttl Bl i


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Item: Two Stage: One Stage:

Level Of Bi-orientation Higher (Lower Preform Temp) Lower

Material Distribution Optimum (Preform Design) Some issues under neck

stretching

AA Level Low High

Moisture Pick Up During Preform Storage No moisture pick-up

Scrap Rate Low (< 1%) High (2 - 4%)

One Stage vs. Two Stage Process

PET Bottle Blowing

UPDATED: MARCH 2003

PET Bottle Blowing


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80%

15%

3%

PET Resin

Other

Labour

Scrap

Cost Breakdown of a PET Bottle

Resin prices are a key cost when evaluating economics

PET Bottle Blowing

PET Bottle Blowing


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Process Overview

PREFORM

RECEIVING/

INSPECTION

PET BOTTLE

BLOWING

Process: Sampling

COC/COA

Incoming Tests


Preheating oven

Stretchblowing


Intrinsic Viscosity

Visual Defects


different I.V.s


blow timing

PREFORM

STORAGE

Preform storage

Storage time/temp

Relative humidity

BEVERAGE

PLANTEMPTY PET

STORAGE

Temperature

Humidity

Odor pickup

Empty PET

bottle storage

PET Bottle Blowing

PET Bottle Blowing


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Empty PET Bottle Storage

PET Bottle Blowing

First In, First Out principle should be applied in the caseof empty PET bottle inventory

PET bottles should be stored in a dry environment. Ideal

conditions are Storage temperature: 5C/41F to 35C/95F

Relative Humidity: < 60%

Keep PET bottles away from substances that emit strongodors and direct sunlight (PET transportation andwarehousing)

Lot Identification:

Lot code Neck finish type

Date

Shift

Production date

Color

Resin type

PET Bottle Weight

PET Bottle Blowing


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Empty PET Bottle Storage

PET Bottle Blowing

PET bottles are normally packed into cardboard trayswhich are placed on wooden pallets (up to 8 layers in

height)

These pallets of empty PET bottles are normallystretch-wrapped and stored in the warehouse at no

more than 4 pallets high.

Silo storage is used as an alternative with somebeverage plants.

While no specific age limit exists, bottles more than 6months old may be subject to secondary shrinkage,rendering them unsuitable for use (Fill height issues)

PET Bottle Blowing


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Key Take-Aways

PET Bottle Blowing

Preforms are purchased only from approved suppliers

COC/COA reduces the need on the PET blowingfacility to perform incoming testing on the preforms

Preforms should be stored for 24 hours in the same

room prior to PET bottle blowing PET bottles should be stored in a dry environmentAcceptable conditions are:

Storage temperature 5C/41F to 35C/95F

Relative Humidity < 60%

Documents

2. PET - PreformManufacturing & Blowing