JPS6044156B2 - resin laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides thermoplastic polyester resin and modified ethylene-
The present invention relates to a resin laminate that is made of a vinyl acetate copolymer and has excellent printability, environmental stress cracking resistance, oil resistance, aroma permeation prevention property, or gas barrier property, and is high in strength.

Conventionally, thermoplastic polyester resins have gas barrier properties,
Although it has extremely good properties in terms of oil resistance and mechanical strength, it is extremely expensive and has high water permeability, so it cannot be used as a single material in the food industry, cosmetics industry, automobile industry, etc. Ku.

It had some flaws. On the other hand, in addition to its low cost, ethylene-vinyl acetate copolymer has good mechanical strength, transparency,
It is used in a wide range of applications from the viewpoints of moldability and hygiene.

However, ethylene-vinyl acetate copolymers have poor gas barrier properties and oil resistance, so when used as food containers for mayonnaise, soy sauce, etc., food cannot be stored for long periods of time. When used as a container, there were drawbacks such as a large amount of gasoline being lost, and the container swelling and deforming. Various proposals have been made in the past to improve the drawbacks of ethylene-vinyl acetate copolymers, but these have been subject to limitations such as complicating the manufacturing process, increasing costs, and limiting the application design. However, the results have not been satisfactory.

One solution to this problem is to laminate it with resins such as thermoplastic polyester resins, polyamides, and vinyl chloride-vinylidene chloride copolymers, which have properties that compensate for the drawbacks of the ethylene-vinyl acetate copolymers. Although it is considered,
Originally, the ethylene-vinyl acetate copolymer had a low affinity with the above three resins, as expected from its chemical structure, and had the disadvantage that it easily peeled off when the two resins were simply melt-pressed.

Although there has been a proposal to provide an adhesive layer between these two resin layers, this requires a separate adhesive coating process, which has the disadvantage of complicating the manufacturing process. An object of the present invention is to provide a resin laminate that has the advantages of gas barrier properties, oil resistance, and low cost, and in which both resin layers are firmly bonded without an adhesive.

The present invention aims to achieve the above object, and includes:
Modified ethylene-vinyl acetate copolymers modified with acrylic acid or maleic anhydride and having a concentration of 0.16 to 1% by weight (including those diluted with unmodified polyolefins)
and a layer of thermoplastic polyester resin are laminated in a molten state, and the moisture permeability according to JIS-Z-0208 is 10 g/
ASTM-D-1434-58 oxygen permeability of 200 at d/2.411r or less at 30°C and 0% relative humidity
The present invention provides resin laminates for films, sheets, containers, etc. that have a cc/d・24 hr-Atm or less.

The modified ethylene-vinyl acetate copolymer used in the present invention is usually a commercially available ethylene-vinyl acetate copolymer or a polyolefin (a homopolymer of α-olefins such as ethylene and propylene, as well as homopolymers of ethylene and other α-olefins). Copolymers with olefins such as ethylene-propylene copolymers, ethylene-butene-1 copolymers, ethylene-hexene-1 copolymers, and crystalline polymers of α-olefins such as propylene-butene-1 are also included.

It also contains small amounts (eg, 5 mole % or less) of other vinyl monomers, such as acrylic acid, acrylic esters, and copolymers of vinyl acetate and ethylene. These polymers and copolymers may be used as a blend. ) and then graft-modified with a modifier. The modifier used in the present invention is acrylic acid or maleic anhydride.

In particular, maleic anhydride is most preferred as shown in the examples below. The modification method is to graft-polymerize the above-mentioned modifier onto the polyolefin.

Graft polymerization can be carried out by melt-kneading the ethylene-vinyl acetate copolymer, a grafting monomer as a modifier, and a radical generator in an extruder, or by melt-kneading the ethylene-vinyl acetate copolymer suspended in an appropriate solvent. There is a method of adding a grafting monomer and a catalyst to the combination and heating and stirring the mixture. The modified product may be diluted with unmodified polyolefin.

In this case, the concentration of the modifier in the resin forming the modified ethylene-vinyl acetate copolymer layer is set to 0.0000. It is necessary to set it to 16-1 weight%.

Furthermore, the thermoplastic polyester resin used in the present invention is obtained by condensation of a saturated dibasic acid and glycols, such as polyethylene terephthalate obtained from ethylene glycol and terephthalic acid, or polyethylene terephthalate obtained from 1,4-butanediol and terephthalic acid. Polyethylene terephthalate copolymers or polyethylene terephthalate copolymers containing saturated dibasic acids such as phthalic acid, isophthalic acid, sebacic acid, adipic acid, azelaic acid, glutaric acid, succinic acid, and oxalic acid as copolymer components in addition to the resulting polybutylene terephthalate. Butylene terephthalate copolymer, and 1,4-cyclohexanedimethanol, diethylene glycol, as a diol component,
A polyethylene terephthalate copolymer or a polybutylene terephthalate copolymer containing propylene glycol or the like as a copolymer component, or a blend thereof.

In carrying out the present invention, a thermoplastic polyester resin may be blended between the modified ethylene-vinyl acetate copolymer layers in order to improve the adhesive strength between the two layers. The blending amount is 0 in the total resin of the modified ethylene-vinyl acetate copolymer layer.
．． 05 to 5% by weight.

The thermoplastic polyester resin to be blended may be the same material as the thermoplastic polyester resin layer laminated with the modified ethylene-vinyl acetate copolymer layer, or may be a different material. Linear thermoplastic polyester resins made from aliphatic dibasic acids such as succinic acid, sebacic acid, and adipic acid have better adhesive properties than aromatic thermoplastic polyester resins made from dibasic acids. More preferred. In the present invention, a modified ethylene-vinyl acetate copolymer layer and a thermoplastic polyester resin layer are combined into one layer.
As a method for melting and laminating at a temperature of 80 to 300° C., methods such as an in-die lamination method, an outside-die lamination method, and thermocompression bonding using a press can be used.

At this time, it is preferable that a pressure of 1 kg/d or more acts between both resin layers. In addition, in the case of molding a hollow container using a circular die, the in-die laminate molding method is preferable.

In order for the resin laminate of the present invention to be used for perfume containers, food packaging films, medicine containers, gasoline containers, etc.
The moisture permeability value measured according to JIS-Z-0208 and converted to a thickness of 30p is 10g/D24hr or less, and the ASTM-
The oxygen permeability measured by D-1434-58 using 99.99% pure oxygen at an average pressure difference of 300TI0nHg was 200cc/d・2 at 30°C and 0% relative humidity.
It is necessary that it is 4 hr-Atm or less.

The thickness ratio of the thermoplastic polyester resin layer to the modified ethylene-vinyl acetate copolymer layer is preferably 1 to 50% of the modified ethylene-vinyl acetate copolymer layer. The thermoplastic polyester resin is preferably used in the present invention in a thickness of 20 to 60 microns because it has excellent gas barrier properties, aroma permeation prevention properties, moldability, and is expensive.

Modified ethylene-vinyl acetate copolymer blended with unmodified polyolefin has superior rigidity and is cheaper than thermoplastic polyester resin, so it is used thicker than thermoplastic polyester resin layer, and is preferably used although it varies depending on the application. It is used with a wall thickness of about 40 μm to 37 μm.

Therefore, the thickness ratio of the thermoplastic polyester resin layer to the modified ethylene-vinyl acetate copolymer layer is 25 to 50% for film-like materials that require flexibility, and 1 to 15% for containers that require rigidity. For sheet materials that require both flexibility and rigidity, it is preferably about 6 to 30%.

The embodiment of the present invention has a two-layer structure of a modified ethylene-vinyl acetate copolymer layer/thermoplastic polyester resin layer, and
Modified ethylene-vinyl acetate copolymer layer/thermoplastic polyester resin layer/modified ethylene-vinyl acetate copolymer layer,
Three-layer structure including unmodified polyolefin layer/modified ethylene-vinyl acetate copolymer layer/thermoplastic polyester resin layer, thermoplastic polyester resin layer/modified ethylene-vinyl acetate copolymer resin layer/thermoplastic polyester resin layer, unmodified polyolefin It includes a five-layer structure of layer/modified ethylene-vinyl acetate copolymer layer/thermoplastic polyester resin layer/modified ethylene-vinyl acetate copolymer layer/unmodified polyolefin layer. The resin layer that becomes the inner layer in carrying out the present invention is appropriately selected depending on the intended use.

For example, in the case of a container for a liquid that swells an ethylene-vinyl acetate copolymer such as gasoline, toluene, carbon tetrachloride, etc., the inner layer is a thermoplastic polyester resin layer and the outer layer is a modified ethylene-vinyl acetate copolymer layer.

On the other hand, when ethylene-vinyl acetate copolymer is not mixed with the contents of cosmetics or soy sauce, and consumers require a container with an excellent appearance, a modified ethylene-vinyl acetate copolymer is used in the inner layer. A thermoplastic polyester resin layer is used as the outer layer.

The thermoplastic polyester resin used as the gas barrier resin for the laminate of the present invention is superior to other gas barrier resins, such as polyamide, in the following points.

(a) The oxygen permeation prevention property is equivalent to that of polyamide, but the moisture permeability and fragrance permeability are about 1 that of 1 powder.

(Explanation) Mechanical strengths such as bending strength and tensile strength are higher than polyamide, so the strength will be higher for products with the same wall thickness.

(c) The surface hardness is greater than that of polyamide, so it is less susceptible to external damage.

In addition, thermoplastic polyester resins have the following advantages:

(d) Since the surface is smooth, when used as an outer layer, it gives a high-class image to consumers.

(e) Since it absorbs ultraviolet rays, it can prevent the contents from deteriorating due to ultraviolet rays.

(f) Excellent transparency.

Examples will be shown below to further specifically explain the present invention.

Comparative Example 1 0.0 parts of benzoyl peroxide was added to 10 parts of polypropylene powder (MIO.8, specific gravity 0.91). After adding 1.2 parts by weight of maleic anhydride, the mixture was mixed using a Henschel mixer, extruded at 220°C using an extruder with a diameter of 100 TWt1L/D28, and pelletized after cooling with water.

(After dissolving this modified polypropylene in boiling xylene and reprecipitating it with a large amount of acetone, the concentration of maleic anhydride component in the modified polypropylene was measured using infrared absorption spectroscopy, and it was found to be 0.6 % of unmodified polypropylene (1 part by weight of this pellet).
MlO. Ton specific gravity 0.90) 9 heel weight part diameter 1001Tr!
It was extruded into a strand shape at 250° C. using a NIL/D28 extruder, and after cooling with water, it was pelletized.

Using the thus obtained modified polypropylene-containing pellets and polyethylene terephthalate (Arnite A2OO manufactured by Akzo) as raw materials, a multilayer hollow bottle having a volume of 1000 cc and having a polyethylene terephthalate layer as an outer layer was obtained by in-die lamination blow molding.

A 15m wide test piece was cut from the body of the hollow bottle and the peel strength between the two layers was measured, and it was found to be 0.5k9/15Tn.
It was m. The resin temperature during molding was 230°C for pellets containing modified polypropylene and 260°C for polyethylene terephthalate, and the average wall thickness of the body of the multilayer hollow bottle was 40μ for the polyethylene terephthalate layer and 0.57r0ft for the modified polypropylene layer. be.

Comparative Example 2 A multilayer hollow bottle was obtained in the same manner as Comparative Example 1, except that unmodified polypropylene (MIl.2, specific gravity 0.91) was used instead of modified polypropylene.

The peel strength between both layers of the bottle was 0 kg/15 WfL.

Comparative Example 3 A sheet with a wall thickness of 0.5wn was produced using an electric press using the pellets containing the modified polypropylene obtained in Comparative Example 1 as a raw material, and a sheet with a wall thickness of 0.0wn was produced by extrusion molding in advance on this sheet.
A 4wt thermoplastic polyester (Arnite A2OO manufactured by Akzo Corporation) film was placed on it, preheated for 3 minutes at 280°C using an electric press, further pressed at the same temperature for 2 minutes at a pressure of 8k9/CI, and cooled to obtain a laminated sheet. Ta.

The interlayer peel strength of the obtained laminated sheet was 1.0k9/15
It was in order.

Comparative Example 4 The modified polypropylene used in Comparative Example 1 w parts by weight and the unmodified polypropylene (MIλ specific gravity 0.91) 9 parts by weight were combined into a diameter of 1007077! , 230 using an extruder with L/D 28
It was extruded into strands at ℃ and pelletized after cooling with water.

Using the thus obtained pellets as the material for the inner layer and polyethylene terephthalate as the material for the outer layer, the thickness of the polyethylene terephthalate layer was 30 μm and the thickness of the modified polypropylene layer was 60 μm using the in-die laminated inflation method.
A multilayer inflation film was molded.

The interlayer peel strength of the obtained laminated film was 0.3 kg/1
5Tn! n, moisture permeability 3g/d/2 oil r, oxygen permeability 1
It was 5cc/I.24F1r-Atnl.

The resin temperature during molding was 230°C for pellets containing modified polypropylene and 280°C for polyethylene terephthalate.
It was hot. Example 1 10 parts of ethylene-vinyl acetate copolymer (101 specific gravity: 0.9 tons, vinyl acetate content: 2%) and 0.0 parts of maleic anhydride. After adding 0.6 parts by weight of 3,5,5-trimethylhexanoyl peroxide, mix well using a Henschel mixer and form into a strand at 160°C using an extruder with a diameter of 100wt1L/D28. After extrusion and cooling with water, it was pelletized.

(The pellets of this modified ethylene-vinyl acetate copolymer (hereinafter referred to as 1-modified EVAJ) were analyzed by infrared absorption spectroscopy after reprecipitation, and the maleic anhydride content was found to be 0.9%). In order to investigate the effect of the amount of modification of maleic anhydride on adhesion, the modified EVA was mixed with unmodified ethylene-vinyl acetate copolymer in the proportions shown in Table 1 below. (■2
, specific gravity 0.94, vinyl acetate content 1%), diluted modified EVA is used as the inner layer material, and polyethylene terephthalate (Akzo Arnite A2OO) is used as the outer layer material using the in-die lamination method. A bottle was molded, and a test piece with a width of 15 wn was taken out from the body of the resulting hollow bottle, and the interlayer peel strength was measured.

The results are shown in Table 1. In addition, the resin temperature during molding is modified EV
A or its dilution at 180°C, polyethylene terephthalate at 260°C, and the thickness of each layer in the body of the hollow bottle was 60μ for the polyethylene 7 terephthalate layer and 0.0μ for the modified EVA layer.
5? It was hot.

Comparative Example 5J 10 parts of powder of high density polyethylene (MIO.5s specific gravity 0.96), 0.6 parts by weight of 3,5,5-trimethylhexanoyl peroxide, 0.9 parts by weight of maleic anhydride
After adding parts by weight, mix using a Henschel mixer,
The mixture was extruded at 220° C. using an extruder with a diameter of 40 wm 1 L/D28, cooled with water, and then pelletized.

(The obtained pellets had 0.0% of maleic anhydride added.) This modified high-density polyethylene weighed 1 part, unmodified high-density polyethylene (MlO.8. specific gravity 0.95)
9 saliva amount 5 parts, diameter 407077! , L/D28 extruder at 200°C, cooled with water, and then pelletized.

Using the thus obtained pellets containing modified high-density polyethylene as the inner layer material and polyethylene terephthalate as the outer layer material, the thickness of the polyethylene terephthalate layer was 30μ by the in-die laminar inflation method, and the modified high-density polyethylene layer was A multilayer inflation film with a wall thickness of 60 μm was molded.

The interlayer peel strength of the obtained laminated film was 0.4 kg/1
5 moe, moisture permeability is 5 g/d/2 oil r, oxygen permeability is 20 c
It was c/i・24hr-Atm.

The resin temperature during molding was 220° C. for pellets containing modified high-density polyethylene, and 280° C. for polyethylene terephthalate. Comparative Example 6 Using the pellets containing the modified polypropylene obtained in Comparative Example 1 as a raw material, a sheet with a wall thickness of 0.1 gourd was produced using an electric press, and a thermoplastic sheet with a wall thickness of 25 μm was prepared by extrusion molding on this sheet in advance. Polyester resin (Arnite A2O manufactured by Akzo)
Place the film O) on it, preheat it at 250℃ for 3 minutes using an electric press, and then heat it at the same temperature for 2 minutes at a pressure of 10K9/Cl.
Pressure was applied for a minute and the mixture was cooled to obtain a laminated sheet.

The interlayer peel strength of the obtained laminated sheet was 1.0k9/15
Gourd, moisture permeability is 1g/I/2 oil r1 oxygen permeability is 8cc
/d・24hr-Atnl.

Comparative Example 7 The maleic anhydride used in Comparative Example 5 was 0. Capacity%
A linear thermoplastic polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) is mixed with the added high-density polyethylene in the proportions shown in the table below, and this is melt-kneaded using an extruder, extruded into a strand, and after cooling with water, pellets are formed. It became.

0.17 using an electric press using the obtained pellets as raw material.
A WL sheet was prepared, and a 25 μm thick thermoplastic polyester resin (Arnite A2OO manufactured by Akzo Corporation) film prepared by extrusion molding in advance was placed on this sheet, preheated at 250°C for 3 minutes using an electric press, and then heated. 10k9/at the same temperature
Pressure was applied for 2 minutes using Clt pressure, and the mixture was cooled to obtain a laminated sheet.

The interlayer peel strength of the obtained laminated sheet is shown in the same table.

Comparative Example 8 Multilayer inflation was carried out in the same manner as Comparative Example 4, except that ethylene-zinc methacrylate copolymer (Surlyn Al652 manufactured by DuPont) was used as the material for the inner layer, and the resin temperature during molding was 180°C. A film was formed.

The interlayer peel strength of the obtained laminated film was 0.1k9/1
It was 5wn.

Comparative Example 9 In Comparative Example 4, a blown film was molded in the same manner as in Comparative Example 8, except that the ethylene-zinc methacrylate copolymer used in Comparative Example 8 was used instead of the modified polypropylene.

The obtained laminated film had no adhesion at all.

Example 2 Acrylic acid 0. An acrylic acid graft-modified ethylene-vinyl acetate copolymer (hereinafter referred to as 0-modified EVAJ) was prepared in the same manner as in Example 1, except that 0.4 parts by weight of 3,5,5-trimethylhexanoyl peroxide were used.

) was obtained. After reprecipitating this modified EVA pellet, it was analyzed using an infrared absorption spectrum, and the acrylic acid content was found to be 0.
．． It was 5% by weight. Using the obtained modified EVA, a multilayer hollow bottle was molded in the same manner as in Example 1, and the interlayer peel strength between polyethylene terephthalate and modified EVA was measured, and it was found to be 1.5k9/15TnI! It was t. Comparative Example 10 High density polyethylene (MIO.5. Specific gravity 0.96)
After adding 2.0 parts by weight of 3,5,5-trimethylhexanoyl peroxide and 4 parts by weight of maleic anhydride to 10 parts of the powder, the same procedure as in Comparative Example 5 was carried out to obtain 1.0 parts by weight of maleic anhydride. Modified high-density polyethylene with added heel weight % was obtained.

A multilayer inflation film with an inner layer of 60 μm and an outer layer of 30 μm was molded in the same manner as in Comparative Example 5 using this modified high-density polyethylene as an inner layer and polyethylene terephthalate as an outer layer, but it was not satisfactory in terms of extrusion moldability. In other words, uneven thickness distribution was observed on the circumferential surface of the extruded film, and it was not suitable for use as a product as is.

Comparative Example 11 Polypropylene (MIO.8, specific gravity 0.91
) benzoyl peroxide to 10 parts of powder 3. Volume part and maleic anhydride5. Comparative example 1 after adding slag weight
In the same manner as above, a modified polypropylene to which 2.4% by weight of maleic anhydride was added was obtained.

The inner layer was made in the same manner as Comparative Example 1, with this modified polypropylene as the inner layer and polyethylene terephthalate as the outer layer.
A multi-layer hollow bottle with 5TSf1 and an outer layer of 40p (both average wall thicknesses of the bottle body) was molded, but it was unfavorable in terms of extrusion moldability, that is, the wall thickness at the top and bottom of the bottle was large due to significant drawdown. were extremely different, and were unsuitable for use as a product as they were.

remarks

Claims (1)

[Claims] 1 A layer of a modified ethylene-vinyl acetate copolymer (including one diluted with an unmodified polyolefin) graft-modified with acrylic acid or maleic anhydride and whose modifier concentration is 0.16 to 1% by weight, and a thermoplastic Laminated with polyester resin in molten state, moisture permeability is 10g/m^2/
A resin laminate having an oxygen permeability of 200 cc/cm^2.24 hr.atm or less at 30° C. and 0% relative humidity for 24 hr or less.