Biaxially oriented polypropylene film (also known as BOPP film) is a fine chemical product, generally a multi-layer co-extruded film, which is made by co-extruding polypropylene particles into sheets and then stretching them in both the longitudinal and transverse directions.

Biaxially oriented polypropylene film has good physical stability, mechanical strength, and air tightness, high transparency and gloss, and is tough and wear-resistant. It is a widely used printing film. The general thickness is 20 microns to 40 microns, and the most widely used is 20 microns.

Biaxially oriented polypropylene film types include non-heat-sealable film, heat-sealable film, and milky white film; it is suitable for packaging materials for candy, food, medicine, records, clothing, etc.; it can also be compounded with cellophane, aluminum foil, etc. to make composite packaging materials.

Information

Due to the orientation of the stretched molecules, this film has good physical stability, mechanical strength, and air tightness, high transparency and gloss, and is tough and wear-resistant. It is currently the most widely used printing film. The general thickness is 20-40¦Ìm, and the most widely used is 20¦Ìm. The main disadvantage of biaxially oriented polypropylene film is its poor heat sealability, so it is generally used as the outer film of composite film. For example, after being composited with polyethylene film, its moisture resistance, transparency, strength, stiffness and printability are ideal, and it is suitable for holding dry food. Since the surface of biaxially oriented polypropylene film is non-polar, with high crystallinity and low surface free energy, its printing performance is poor, and its adhesion to ink and adhesive is poor. Surface treatment is required before printing and lamination.

Features

Biaxially oriented polypropylene film has the advantages of light weight, non-toxicity, odorlessness, moisture resistance, high mechanical strength, good dimensional stability, good printing performance and good transparency. It has the advantages of high transparency, good gloss, good barrier properties, high impact strength and low temperature resistance. Its disadvantage is that the film is prone to shrinkage during heat sealing (except for heat shrinkable cigarette film using its heat shrinkage properties). Its comprehensive performance is better than moisture-proof

glass paper, polyethylene (PE) film and PET film. BOPP film also has excellent printing effect. Representative physical properties are: turbidity <1.5%; gloss >85%; tensile strength (longitudinal/transverse) >120/200MPa; elongation at break (longitudinal/transverse) <180%/65%; elastic modulus 1700-2500Mpa; brittle temperature -50¡æ.

Due to the directional effect of molecules, the crystallinity is improved, and the tensile strength, impact strength, rigidity, toughness, moisture resistance, and transparency are all improved, and the cold resistance of the film is also improved

It has good gas barrier and moisture resistance

High transparency, good gloss, and good printability

It is non-toxic, odorless, and tasteless, and can be directly used in places where it comes into contact with food and medicine.

Parameters

The performance parameters are as follows:

GB/T5009.60-1996 Analysis method for hygienic standards of polyethylene, polystyrene and polypropylene moldings for food packaging

GB/T6672-1986 Determination of thickness of plastic film and sheet - Mechanical measurement method

GB/T6673-1986 Determination of length and width of plastic film and sheet

GB/T8807-1988 Plastic mirror gloss test Test method

GB9688-1988 Hygienic standard for polypropylene molded products for food packaging

GB/T10006-1988 Determination method for friction coefficient of plastic film and sheet

GB/T13022-1991 Test method for tensile properties of plastic film

GB/T14216-1993 Test method for wetting tension of plastic film and sheet

Definition

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This standard adopts the following definitions.

Ribbed ribs

The raised longitudinal strips on the surface of the film roll.

Classification

The products are divided into cigarette packaging film (Class A) and general packaging film (Class B) according to different uses. Class A is further divided into ordinary type and heat shrink type.

Specifications

Width: 100mm-1200mm;

Thickness: 15¦Ìm-45¦Ìm;

Special specifications are agreed upon by both parties.

Test methods

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Sampling method

Remove the three layers on the surface of the test film roll, and cut about 20 layers along the width of the film roll for appearance, specifications and physical properties testing. Roll it with a paper core to prevent the sample from being contaminated.

Standard environment for sample state adjustment and testing

According to the provisions of GB/T2918. Standard environment (23/50), the allowable deviation level is 2. The state adjustment time is not less than 4h, and the test is carried out under this condition.

Width and length

According to the provisions of GB/T6673.

Thickness

According to the provisions of GB/T6672.

The accuracy of the measuring instrument is less than or equal to 0.2¦Ìm. The thickness deviation is calculated using the maximum deviation value.

The average thickness is the arithmetic mean of the thickness of each point measured. The average thickness deviation is the percentage of the difference between the average thickness and the nominal thickness to the nominal thickness.

Appearance

Lightly flatten under natural light or light, and visually inspect. The end face winding irregularity is measured with a measuring tool with an accuracy of 0.5mm.

Tensile strength and elongation at break

According to the provisions of GB/T13022. The sample is a long strip with a length of 150mm and a width of (15¡À0.1mm). The distance between the fixtures is 100mm, and the test speed is (250¡À25)mm/min.

Haze is carried out in accordance with the provisions of GB/T2410. 6.9 Gloss is carried out in accordance with the provisions of GB/T8807. The angle of incidence is 450. 6.10 The coefficient of friction shall be determined in accordance with the provisions of GB/T10006.

The tensile elastic modulus shall be determined in accordance with the provisions of GB/T13022. 6.13 The wetting tension shall be determined in accordance with the provisions of GB/T14216.

The hygienic properties shall be determined in accordance with the provisions of GB/T5009.60. [2-3]

Inspection rules

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Batching

The films produced continuously for no more than one week with the same raw materials, the same process conditions and the same specifications shall be a batch, and each batch shall not exceed 200t.

Sampling

Physical and mechanical properties and hygienic properties shall be randomly selected from one roll of each batch of products.

Factory inspection

Factory inspection includes all items in the technical requirements except for moisture permeability and hygienic properties.

Type inspection

Type inspection includes all items in the technical requirements. Type inspection should be carried out in any of the following situations:

a) Trial design and identification of new products or old products for production conversion;

b) After formal production, if there are major changes in structure, materials, and processes that may affect product performance;

c) During normal production, inspection should be carried out every six months;

d) When the product is resumed after a long period of suspension;

e) When there is a significant difference between the factory inspection result and the last type inspection;

f) When the national quality supervision agency proposes a requirement for type inspection.

Determination of qualified items

If one of the dimensional deviation and appearance of the film is unqualified, the roll is unqualified. If one of the physical and mechanical properties of the film is unqualified, the original batch should be doubled and the unqualified item should be re-sampled. If the re-inspection result is still unqualified, the physical and mechanical properties are unqualified.

Sanitary performance

If one of the items is unqualified, the sanitation performance is unqualified.

Determination of qualified batches

If the physical and mechanical properties and hygienic properties are all qualified, the batch is determined to be qualified.

Determination of quality grade

The product quality grade is determined by the lowest grade of the inspection results of all items.

Other information

Mark

The film roll and the packaging box should have a certificate of conformity and a registered trademark, and the product name, specification, length, weight, treatment surface, batch number, production date, shift, grade, inspection stamp, brand name, factory address, implementation standard number and "moisture-proof, heat-proof, and impact-proof" marks should be noted.

Packaging

Each roll of film is protected by pads at both ends, wrapped with film, and plugged with plastic plugs at both ends. Products with a film width greater than 500mm should be supported by plywood and loaded into the box and tied tightly. Special packaging is agreed upon by the supply and demand parties.

Transportation

It should be handled with care during transportation to prevent mechanical collision and sun and rain.

Storage

The film should be stored in a clean, dry warehouse, more than 2m away from heat sources, and not exposed to direct sunlight. The storage period should not exceed one year from the production date.

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