CN105542272B - A kind of polyethylene base film specially used for compounding with polyvinyl alcohol film and its preparation method - Google Patents

Abstract

Polyethylene basis film compound with polyvinyl alcohol film and preparation method thereof is exclusively used in the invention discloses a kind of.This polyethylene basis film raw material is by polyethylene（PE）70‑90.5%（Wt%, similarly hereinafter）；Ethylene acrylic acid co polymer（EAA）5‑15%；Polyethylene glycol oxide（PEO)3‑10%；Polyethylene glycol（PEG)1‑3%；Precipitated silica 0.5 2.0% forms.It is granulated after and through double screw extruder at 120 180 DEG C, Single screw extrusion is in 160 180 DEG C of blowings or casting film-forming.With this modified polyethylene（PE）Film and polyvinyl alcohol（PVA）It can be greatly improved after Film laminated to the erosion damage under moisture or high humidity environment, laminated film is in relative humidity RH:Handled under 90% environment（23℃）48 it is small when after, its peel strength >=2.0N/15min.

Description

A kind of polyethylene base film specially used for compounding with polyvinyl alcohol film and its preparation method

technical field

The invention relates to the field of films, in particular to a polyethylene base film specially used for compounding with polyvinyl alcohol films and a preparation method thereof.

Background technique

Polyethylene plastic (PE) film is widely used in the packaging of fruits, vegetables and other foods because of its non-toxic, tasteless, hygienic and safe, and water vapor barrier. However, in use, due to the low barrier properties of polyethylene film to oxygen, carbon dioxide, etc., the packaged food is prone to deterioration or quality degradation due to oxidation within a certain period of time. In order to improve the performance of packaging films, at present: 1) Use films with excellent barrier properties for composite use, such as using EVOH, PVDC and other films with excellent barrier properties to prepare films for packaging food; 2) Aluminum plating polyolefin films etc., are all to improve the barrier performance of polyolefin substrates to ensure the quality of food and other packaged objects; 3) or directly use aluminum foil for compounding and use it as packaging materials, etc., all in order to improve the barrier properties of packaging materials Performance and improve storage time and storage quality of packaged items. At present, high barrier materials such as EVOH, PVDC, etc. are not only expensive, but also difficult to process, and their barrier properties are not as good as PVA; although the barrier properties of composite films can be greatly improved by using aluminum thin films, the packaging materials can only be Opaque packaging materials, and the use of PVA for composite production of packaging materials can greatly improve the barrier performance of the composite film, and can also maintain the transparency of the composite film; at the same time, PVA is a cheap and high-quality material with excellent barrier properties. Real value for development usage.

Since polyvinyl alcohol (PVA) is a highly polar water-soluble polymer material, and other film substrate polyethylene (PE) films to be used in combination are non-polar polymer materials, it is very difficult and unattainable. Therefore, the intermediate layer must be used for bonding and compounding to ensure the integrity of the compounded film. Even if the intermediate adhesive layer is used, the composite film will be damaged or even completely separated or the composite layer will be detached due to the strong hygroscopicity of polyvinyl alcohol (PVA) in the presence of moisture or in a high-humidity environment; this is because After polyvinyl alcohol (PVA) absorbs water, it penetrates into the middle layer and polyethylene (PE) composite layer through the film, and because the non-polar surface (ie oily surface) of polyethylene film (PE) is very easy to produce in the presence of moisture The separation of oil and water leads to the separation and detachment of the composite surface of the composite film, which reduces the performance of the composite film and even completely loses the performance of the composite film

The purpose of the present invention is to provide a perfect solution for developing a packaging material with high barrier property and low price: by developing a polyethylene (PE) specially used for compounding with polyvinyl alcohol (PVA) ) basic film, this polyethylene film can greatly improve the adhesion and compatibility to polar polyvinyl alcohol after modification by the technology of the present invention, thereby ensuring the composite quality and use properties of the composite film. This composite film is a new type of packaging material with high barrier properties, excellent mechanical and physical properties, printable and heat-sealable. Composite films can be widely used in the packaging of fresh foods such as fruits, vegetables, eggs and poultry; they can also be used in the direct packaging of other foods; they can also be used in the packaging and storage of active items such as cosmetics and medicines.

Contents of the invention

The invention is a polyethylene base film specially used for compounding with a polyvinyl alcohol film and a preparation method thereof, which is realized through the following technical scheme, and the specific technical scheme is as follows.

A polyethylene base film specially used for compounding with polyvinyl alcohol film. The raw material of the polyethylene base film is composed of the following materials and proportions. After the raw materials are mixed, they are granulated by a twin-screw extruder, and then extruded and blown into The name of each component of the polyethylene base film raw material and the proportion of each component to the total mass of the raw material are as follows:

Polyethylene 70–90.5

Ethylene-acrylic acid copolymer (EAA) 5-15

Polyethylene oxide 3-10

Polyethylene glycol 1-3

Precipitated silica 0.5-2.0.

A kind of preparation method of the above-mentioned polyethylene base film that is specially used for compounding with polyvinyl alcohol film, the preparation steps of this method are as follows:

1) First add polyethylene (PE), ethylene-acrylic acid copolymer (EAA) and polyethylene oxide (PEO) into the high-speed mixer, and mix at low speed (100-300 rpm) for 3-5 minutes;

2) Then add polyethylene glycol (PEG), mix at high speed (500 - 800 rpm) for 3-5 minutes, and finally add precipitated silica, mix at high speed (500 - 800 rpm) for 5–10 minutes Minutes, turn to low speed (100 rpm) to discharge;

3) The mixed material is mixed and granulated by a twin-screw extruder;

4) The granulated material is then extrusion blow molded or extrusion cast to make a polyethylene base film specially used for compounding with polyvinyl alcohol film.

Further, the twin-screw extruder in step 3) performs mixing and granulation, and the extrusion zone temperature is 120/140/150/160/170/180/180/160 °C; after granulation, it is extruded and blown into The film temperature is 160 - 180°C.

Further, the polyethylene in step 1) is film-grade low-density polyethylene (LDPE), film-grade linear low-density polyethylene (LLDPE) or film-grade high-density polyethylene (HDPE); the amount of polyethylene used is 70-90.5% of the total mass of raw materials, other raw materials are ethylene-acrylic acid copolymer (EAA), polyethylene oxide, polyethylene glycol and precipitated silica.

Further, the ethylene-acrylic acid copolymer (EAA) is an ethylene-acrylic acid copolymer (EAA) with an acrylic acid or acrylate AA content of 18-35%; its main use is as polyethylene (PE) and polyethylene oxide (PEO) as a compatibilizer in blending, so that polyethylene oxide (PEO) can be better dispersed and compatible in polyethylene (PE); the use amount of the ethylene-acrylic acid (EAA) copolymer is the total amount of raw materials 5 - 15% of the mass.

Further, the polyethylene glycol (PEG) described in step 2) is polyethylene glycol (PEG) with a molecular weight of 200-800; its main purpose is to disperse and precipitate silica; the polyethylene glycol is used The amount is 1-3% of the total mass of raw materials.

Further, the polyethylene oxide (PEO) described in step 1) is used as the main substance to modify the surface polarity of polyethylene (PE), and it is also a water-soluble polymer with strong polarity. Vinyl alcohol (PVA) has a certain degree of compatibility, and polyethylene oxide (PEO) is also thermoplastic. In the presence of a certain compatibilizer, it can form a film together with polyethylene (PE) through thermoplastic blending; use The amount is 3-10% of the total mass of raw materials.

Further, the precipitated silica described in step 2) is 5000-8000 mesh precipitated silica, and its main function is to improve the opening performance of the modified polyethylene (PE) film instead of using general polyethylene film (PE) commonly used blocking agents (such as stearic acid, stearate, and other aliphatic amides); the amount of precipitated silica used is 0.5-2.0% of the total mass of raw materials.

Compared with the prior art, the present invention has the following advantages and technical effects:

1) Polyethylene (PE) is modified by adding a substance similar in polarity and performance to polyvinyl alcohol (PVA) - polyethylene oxide (PEO). Polyethylene oxide (PEO), like polyvinyl alcohol (PVA), is an excellent water-soluble polymer, and the aqueous solutions of the two have certain compatibility; polyethylene oxide (PEO) is also thermoplastic, suitable for thermoplastic Processing can be satisfied with the blending modification of polyethylene (PE), thereby effectively improving the surface energy of polyethylene (PE) film, making its surface have chemical components similar in polarity to polyvinyl alcohol, so it can greatly improve Compounding with polyvinyl alcohol and compounding qualities.

2) Ethylene-acrylic acid copolymer (EAA) is selected as the compatibilizer for blending polyethylene (PE) and polyethylene oxide (PEO), because EAA not only has excellent compatibility with polyethylene, but also has excellent compatibility with polyethylene oxide (PEO). (PEO) also has a certain degree of compatibility, and it also has a unique property with polyethylene oxide (PEO), that is, polyacrylic acid can form a complex with polyethylene oxide (PEO), which can further improve mutual compatibility. stability. More importantly, this complex can make the extremely water-soluble polyethylene oxide (PEO) completely insoluble in the presence of moisture or in a high-humidity environment. The mutation of this property can better provide composite films Protection against damage to composite layers due to moisture or high humidity attack. Experiments have proved that after the composite film of polyethylene (PE) base film and polyvinyl alcohol (PVA) modified by the technology of the present invention is treated (23°C) for 48 hours at a relative humidity RH: 90%, its peeling The strength can be kept ≥ 2.0N/15min; while the composite film of polyethylene (PE) film and polyvinyl alcohol film that is generally not modified is used, after being treated under the same conditions above, the composite film has begun to partly separate and detach automatically.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples, but the implementation and protection scope of the present invention are not limited thereto.

Example 1

The name of each raw material component of the polyethylene base film and the proportion of each component to the total mass of the raw material are as follows:

Film grade high density polyethylene (HDPE) 90.5

Ethylene-acrylic acid copolymer (AA content: 18%) 5

Polyethylene oxide (PEO) 3

Polyethylene glycol (PEG-400) 1

Precipitated white carbon black (5000 mesh) 0.5

According to the above-mentioned components, first add film-grade high-density polyethylene, ethylene-acrylic acid copolymer (AA content: 18%) and polyethylene oxide into a high-speed mixer, and mix at a low speed of 100 rpm for 5 minutes; then add Polyethylene glycol (PEG-400), mix at 500 rpm for 5 minutes at high speed, finally add precipitated silica (5000 mesh), mix at high speed (500 rpm) for 10 minutes, turn at low speed (100 rpm) / min) discharge; the mixed material is kneaded and granulated by a twin-screw extruder; It is extruded and blown into film, and the partition temperature is 160/165/170/180°C to make a polyethylene base film specially used for compounding with polyvinyl alcohol film. The film is used as the base film to compound with the polyvinyl alcohol film. The peel strength of the composite film was 2.5N/15min after being treated at relative humidity RH:90% (23℃) for 48 hours.

Example 2

The name of each raw material component of the polyethylene base film and the proportion of each component to the total mass of the raw material are as follows:

Film grade low density polyethylene (LDPE) 78.5

Ethylene-acrylic acid copolymer (AA content: 35%) 10

Polyethylene oxide (PEO) 8

Polyethylene glycol (PEG-800) 2

Precipitated white carbon black (8000 mesh) 1.5

According to the above-mentioned components, first add film-grade low-density polyethylene, ethylene-acrylic acid copolymer (AA content: 35%) and polyethylene oxide into the high-speed mixer, and mix at a low speed of 300 rpm for 3 minutes; then add Polyethylene glycol (PEG-800), mix at 800 rpm for 5 minutes at high speed, finally add precipitated silica (8000 mesh), mix at high speed (500 rpm) for 10 minutes, turn at low speed (100 rpm) / min) discharge; the mixed material is kneaded and granulated by a twin-screw extruder; It is extruded and blown into film, and the partition temperature is 160/165/170/180°C to make a polyethylene base film specially used for compounding with polyvinyl alcohol film. The film is used as the base film to compound with the polyvinyl alcohol film. The peel strength of the composite film was 2.3N/15min after the composite film was treated at relative humidity RH:90% (23℃) for 48 hours.

Example 3

The name of each raw material component of the polyethylene base film and the proportion of each component to the total mass of the raw material are as follows:

Film grade linear low density polyethylene (LLDPE) 70

Ethylene-acrylic acid copolymer (AA content: 28%) 15

Polyethylene oxide (PEO) 10

Polyethylene glycol (PEG-600) 3

Precipitated white carbon black (6000 mesh) 2

According to the above-mentioned components, first add film-grade linear low-density polyethylene, ethylene-acrylic acid copolymer (AA content: 28%) and polyethylene oxide into a high-speed mixer, and mix at a low speed of 300 rpm for 5 minutes; Then add polyethylene glycol (PEG-600), mix at 600 rpm for 5 minutes at high speed, finally add precipitated silica (6000 mesh), mix at high speed (800 rpm) for 5 minutes, turn to low speed ( 100 rpm) discharge; the mixed material is mixed and granulated by a twin-screw extruder; The material is then extruded and blown into a film, and the temperature of the partition is 160/165/170/180°C to make a polyethylene base film specially used for compounding with polyvinyl alcohol film. The film is used as the base film to compound with the polyvinyl alcohol film. The peel strength of the composite film was 3.1N/15min after being treated at relative humidity RH:90% (23℃) for 48 hours.

Example 4

The name of each raw material component of the polyethylene base film and the proportion of each component to the total mass of the raw material are as follows:

Film grade high density polyethylene (HDPE) 85

Ethylene-acrylic acid copolymer (AA content: 28%) 8

Polyethylene oxide (PEO) 5

Polyethylene glycol (PEG-200) 1

Precipitated silica (5000 mesh) 1

According to the above-mentioned components, first add film-grade high-density polyethylene, ethylene-acrylic acid copolymer (AA content: 28%) and polyethylene oxide into a high-speed mixer, and mix at a low speed of 200 rpm for 5 minutes; then add Polyethylene glycol (PEG-200), mix at 600 rpm for 4 minutes at high speed, finally add precipitated silica (5000 mesh), mix at high speed (800 rpm) for 8 minutes, turn to low speed (100 rpm) / min) discharge; the mixed material is kneaded and granulated by a twin-screw extruder; It is extruded and blown into film, and the partition temperature is 160/165/170/180°C to make a polyethylene base film specially used for compounding with polyvinyl alcohol film. The film is used as the base film to compound with the polyvinyl alcohol film. The peel strength of the composite film was 2.8N/15min after the composite film was treated at relative humidity RH:90% (23℃) for 48 hours.

Example 5

The name of each raw material component of the polyethylene base film and the proportion of each component to the total mass of the raw material are as follows:

Film grade low density polyethylene (LDPE) 75

Ethylene-acrylic acid copolymer (AA content: 18%) 12

Polyethylene oxide (PEO) 8

Polyethylene glycol (PEG-400) 3

Precipitated white carbon black (8000 mesh) 2

According to the above-mentioned components, first add film-grade low-density polyethylene, ethylene-acrylic acid copolymer (AA content: 18%) and polyethylene oxide into a high-speed mixer, and mix at a low speed of 200 rpm for 5 minutes; then add Polyethylene glycol (PEG-400), mix at 800 rpm for 3 minutes at high speed, finally add precipitated silica (8000 mesh), mix at high speed (500 rpm) for 10 minutes, turn at low speed (100 rpm) / min) discharge; the mixed material is kneaded and granulated by a twin-screw extruder; It is extruded and blown into film, and the partition temperature is 160/165/170/180°C to make a polyethylene base film specially used for compounding with polyvinyl alcohol film. The film is used as the base film to compound with the polyvinyl alcohol film. The peel strength of the composite film was 2.7N/15min after the composite film was treated at relative humidity RH:90% (23℃) for 48 hours.

The above embodiments are only used to illustrate the technical solution of the present invention, not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present invention can still be modified or some technical features can be equivalently replaced without departing from the spirit of the technical solution of the present invention , which should all be included in the scope of the technical solution requested by the present invention.

Claims (8)

1. a kind of be exclusively used in the polyethylene basis film compound with polyvinyl alcohol film, it is characterised in that the polyethylene basis is thin Film raw material is made of following material and ratio, is granulated after raw material mixing by double screw extruder, then extruded blowing again Film forming；The ratio that each material component title of polyethylene basis film and each component account for raw material gross mass is：

Polyethylene 70-90.5

Ethylene-acrylic acid copolymer 5-15

Polyethylene glycol oxide 3-10

Polyethylene glycol 1-3

Precipitated silica 0.5-2.0.

2. a kind of method for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film described in claim 1 is prepared, It is characterized in that, preparation process is as follows：

1）Each component metering as described in claim 1, first adds polyethylene, ethylene-acrylic acid copolymer and polyethylene glycol oxide Enter into homogenizer, mixed 3-5 minutes under 100-300 revs/min of low speed；

2）Polyethylene glycol is added, starts and mixes 3-5 minutes for 500-800 revs/min at a high speed, be eventually adding precipitated silica, Mixed 5-10 minutes under 500-800 revs/min of high speeds, turn low speed discharging；

3）Mixed material carries out mixing granulator through double screw extruder；

4）Extruded blowing or extrusion curtain coating are made and are exclusively used in the polyethylene compound with polyvinyl alcohol film material after granulation again Basis film.

A kind of 3. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 1）The polyethylene is Film grade low density polyethylene, film-grade linear low density polyethylene (LLDPE) or thin Film level high-density polyethylene；The polyethylene usage amount is the 70-90.5% of raw material gross mass；Other material components for ethene- Acrylic copolymer, polyethylene glycol oxide, polyethylene glycol and precipitated silica.

A kind of 4. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 1）The polyethylene glycol oxide usage amount is the 3-10% of raw material gross mass.

A kind of 5. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 1）The ethylene-acrylic acid copolymer is ethene-the third of the acrylic acid AA contents 18-35% Olefin(e) acid copolymer；The ethylene-acrylic acid copolymer usage amount is the 5-15% of raw material gross mass.

A kind of 6. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 2）The polyethylene glycol is the polyethylene glycol of molecular weight 200-800；The polyethylene glycol uses Measure as the 1-3% of raw material gross mass.

A kind of 7. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 2）The precipitated silica is the precipitated silica of 5000-8000 mesh；The precipitation method White carbon usage amount is the 0.5-2.0% of raw material gross mass.

A kind of 8. preparation side for being exclusively used in the polyethylene basis film compound with polyvinyl alcohol film according to claim 2 Method, it is characterised in that step 3）The double screw extruder carries out mixing granulator, and extrusion zone temperature is 120/140/150/ 160/170/180/180/160 ℃；After granulation through extrusion-blown modling film-forming temperature be 160-180 DEG C.