JPH0376663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A Technical Field of the Invention The present invention provides a material having excellent blocking resistance and slip resistance, in which one of the surfaces is coated with a resin layer consisting of a specific mixing ratio of two specific types of adhesives. The present invention relates to a saponified ethylene-vinyl acetate copolymer film having a specific composition for thermal lamination that can be used practically without any problems.

B. Prior Art and its Problems Conventionally used plasticized polyvinyl chloride films or sheets, generally referred to as flexible polyvinyl chloride, have an industrial content of about 25% by weight.
As mentioned above, in most cases, a large amount of plasticizer (more than 30% by weight) is usually blended, and for this reason, although the sheet etc. is widely used to take advantage of its favorable properties, the plasticizer migrates to the surface. However, there is a need for a coating material that can cover the surface and eliminate this drawback.

If a soft PVC sheet is used for a desk mat or document holder, for example, and it comes into contact with a document copied by an electrostatic copier, the printing ink will adhere to the soft PVC sheet in a very short period of time, causing the document to become damaged. If the soft vinyl chloride sheet is damaged or the soft vinyl chloride sheet becomes contaminated,
There is a problem in that characters on the printed surface cannot be read. In addition, it is made from soft polyvinyl chloride, so-called PVC leather.
Furniture, office equipment, etc. coated with the leather, and even wallpaper made essentially of soft polyvinyl chloride, are susceptible to contamination due to migration and exudation of the plasticizer onto the surface. There is a problem that must be solved that the contamination is difficult to wipe off. Furthermore, soft polyvinyl chloride films or sheets are preferably used for agricultural purposes such as greenhouse cultivation due to their superior heat retention properties compared to polyolefin films or sheets, but over a relatively long period of time, When used, the plasticizer migrates to the surface and oozes out, staining the surface, resulting in a decrease in light transmittance, which poses a similar technical problem. Although there have been many attempts to improve this drawback, no one has yet been found that achieves the objective and is satisfactorily put to practical use. The reality is that seats have been long-awaited.

On the other hand, there have been attempts to eliminate this drawback by laminating other thermoplastic films on the flexible polyvinyl chloride film or sheet. Examples of coating films that have been put into practical use include acrylic resin films that can be easily adhered to a film or sheet substantially made of soft polyvinyl chloride by thermal lamination without using an adhesive to form a coating layer. There is. However, the effect of preventing the plasticizer migration and oozing is practically not observed. Other thermoplastic resins are
The flexible polyvinyl chloride film or sheet can be fabricated without the use of adhesives by the thermal lamination method, which is the easiest and most easily accepted by the polyvinyl chloride film or sheet manufacturers, and which is technologically the most simple and easily adopted. It is glued to the sheet and the coating cannot be applied. Under these circumstances, as with the acrylic resin, the manufacturer can immediately apply the coating with good adhesive strength by thermal lamination without having to apply an adhesive. There is a strong need for a film for thermal lamination that can also prevent the migration and oozing of the liquid onto the surface.

C Structure, purpose, and effect of the present invention The present invention is characterized in that one of the surfaces contains 60% vinyl chloride component.
Consisting of a vinyl chloride copolymer (A) containing ~99 mol% and 40 to 1 mol% of vinyl acetate and/or (meth)acrylic acid ester components, and a reactive polyurethane polymer (B) containing an isocyanate group, An ethylene-vinyl acetate copolymer with an ethylene content of 20 to 60 mol% and a saponification degree of vinyl acetate component of 95% or more, coated with an adhesive layer with a mixing ratio (weight) of A/B = 2/3 to 6. The present invention aims to provide a film for thermal lamination made of EVOH (hereinafter referred to as EVOH).

The film for thermal lamination of the present invention has excellent blocking resistance and slip property, and also exhibits excellent adhesion to various thermoplastic resin films, sheets, and papers, and has little deterioration over time before lamination. There is also little deterioration in adhesive properties after lamination. Furthermore, it has excellent plasticizer resistance and plasticizer migration/exudation resistance, so it has excellent stain resistance and also has good wiping properties.

In particular, the thermal lamination film of the present invention exhibits remarkable effects when laminated on a polyvinyl chloride film or sheet containing a plasticizer.

D. More detailed description of the present invention One of the most important requirements for the thermal lamination film of the present invention is a resin having thermal adhesive properties that coats one of the surfaces of the EVOH film. The resin must exhibit good adhesion to EVOH and also to the material to be heat laminated, such as plasticized polyvinyl chloride, and the coated EVOH film must have anti-blocking properties. It has good slip properties and has a long shelf life after being coated as a film for thermal lamination. ). The adhesive resin used in the present invention contains 60 to 99 mol% of vinyl chloride component and 40% of vinyl acetate component and/or (meth)acrylic acid ester component.
Vinyl chloride copolymer (A) containing ~1 mol% and reactive polyurethane polymer containing isocyanate groups (B)
and the mixing ratio (weight) of A/B is 2/
3 to 6.

Here, the vinyl chloride copolymer contains 70 to 95 mol% of vinyl chloride component and vinyl acetate and/or
or (meth)acrylic acid ester component from 30 to 5
It is more preferable to use mol%. In addition, vinyl acetate and/or (meth)acrylic ester components include vinyl acetate components, (meth)acrylic ester (methyl esters, ethyl esters, etc.) components, or both of these components. It is preferable to use one or both components. It is also possible to use vinyl chloride copolymers containing these components modified with a third component such as unsaturated organic acids such as maleic acid and itaconic acid or their anhydrides, and (meth)acrylic acid. Among these, those modified with maleic anhydride are more preferred. The preferred content of these third components is 0.1 to 5 mol%.

The solvent for the copolymer is preferably methyl ethyl ketone, ethyl acetate, or butyl acetate, and the diluent is preferably methyl ethyl ketone, toluene, or the like. Reactive polyurethane polymers containing isocyanate groups are polymers having two or more hydroxyl groups in the molecule, such as ethylene glycol,
Polyester obtained by polycondensation of propylene glycol and adipic acid, or polymers with hydroxyl groups in the molecule obtained by partial saponification of a copolymer of vinyl acetate and vinyl chloride, etc. Compounds having groups, e.g. 1
One obtained by mixing a reaction product of 1,6-hexamethylene glycol with 2 moles of 2,4-tolylene diisocyanate, or a reaction product with 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate. It is. Furthermore, a compound having two isocyanate groups in the molecule may be used alone.
As the solvent for the polymer, ethyl acetate, butyl acetate, methyl ethyl ketone, toluene, xylene, etc., which have no reactivity with isocyanate groups, are preferably used.

When the vinyl chloride copolymer (A) is used alone, the coating is provided on an EVOH film, and this is heat laminated to a plasticized polyvinyl chloride sheet, followed by the copolymer (A) layer. The interlayer adhesion with the EVOH layer is low and cannot be practically satisfactory. On the other hand, when the reactive polyurethane polymer (B) containing isocyanate groups is used alone, the adhesive strength is sufficient, but the thermal lamination film has
It exhibits blocking properties and poor slip properties, making it unsuitable for practical use. Only by using a mixture of A and B can this disadvantage be eliminated,
Furthermore, the film for thermal lamination of the present invention has sufficient adhesive strength during thermal lamination, and has a long shelf life with no practical deterioration over time. Mixing ratio of A and B (weight) A/B is 2/
If it is not in the range of 3 to 6, it will not be possible to eliminate the above-mentioned drawbacks and obtain a film with good blocking resistance and slip resistance. If A/B is less than 2/3, the blocking resistance is insufficient, and if it exceeds 6, the adhesive strength is unsatisfactory, and in either case, the shelf life is generally short, which is preferable. do not have.

The amount of the adhesive applied to the EVOH film is 1 to 10 g/m ² , usually 2 to 5 g/m ² . Application of the adhesive by a coating operation includes:
The coating may be carried out by any means known per se, such as gravure coating, roll coating, doctor roll coating, doctor knife coating, bar coating, curtain flow coating, etc.

Thermal lamination of the coated EVOH film can normally be carried out preferably at 120 to 160°C.
At a lower temperature, the adhesive force may not be developed sufficiently, and at a higher temperature, the condition of the EVOH surface may deteriorate, which is not preferable.

The EVOH used in the present invention has an ethylene content of 20 to 60 mol%, preferably 25 to 50 mol%, and a saponification degree of the acetic acid component of 95% or more.

Next, since the thermal lamination film of the present invention exhibits remarkable effects when laminated with a plasticized polyvinyl chloride film or sheet, that is, a plasticized polyvinyl chloride film or sheet containing a plasticizer, this point will be explained below. .

Here, examples of the plasticized polyvinyl chloride film or sheet include those containing 25 to 55% by weight of the following plasticizer which is liquid at 20°C based on the total weight. Examples of plasticizers that are liquid at 20°C include dibutyl phthalate and di-2, which have a melting point of 20°C or less.
-Ethylhexyl phthalate, di-isooctyl phthalate, di-iso-decyl phthalate, di-
Decyl phthalate, di-nonyl phthalate, di-
Phthalate plasticizers such as lauryl phthalate, butyl lauryl phthalate, and butylpenzyl phthalate, phosphate plasticizers such as tricresyl phosphate, tri-butyl phosphate, and tri-2-ethylhexyl phosphate, and chlorine-containing plasticizers such as chlorinated paraffin. Plasticizers that are solid at room temperature include dicyclohexyl phthalate, phthalate plasticizers such as phthalate diesters whose alcohol has 13 or more carbon atoms, polyhydric alcohol plasticizers such as dipentaerythritol fatty acid esters, Examples include trimellitic acid plasticizers such as octyl trimellitate. The ethylene content is 60 mol% or less for these, and the saponification degree is
EVOH of 95% or higher indicates plasticizer resistance and plasticizer migration/leaching resistance. Among these plasticizers, the former is a plasticizer that has particularly remarkable migration and exudation properties;
EVOH causes extremely significant migration and migration of these plasticizers.
It can also prevent oozing. In particular, EVOH with an ethylene content of 55 mol % or less, preferably 50 mol % or less, has extremely satisfactory properties and exhibits virtually no plasticizer permeability.

As the ethylene content increases, the plasticizer permeability gradually decreases, and when the content exceeds 60 mol%, the leaching of the plasticizer to the surface is gradually observed when laminated to a flexible polyvinyl chloride sheet or film. As a result, stain resistance also decreases. On the other hand, as the ethylene content decreases, properties such as plasticizer permeability improve further, but in the region of less than 20 mol%, water resistance becomes poor, and this is not only useful in agricultural films, but also in desk mats and document holders. It is also not suitable for wallpaper, etc., as it may cause swelling or damage to the surface when wiping off contamination caused by mere external factors unrelated to plasticizer leaching using a rag or the like. More preferably, the ethylene content is 25 mol% or more. The EVOH of the present invention has an ethylene content of 20 to 60 mol%, more preferably 25 to 50 mol%.
It is sufficient that the ethylene content is within this range, and it may be a blend of two or more types with different ethylene contents within this range. EVOH, which has an ethylene content in the range of 20 to 60 mol%, has practically satisfactory water resistance, but on the other hand, it is a hydrophilic polymer capable of retaining equilibrium moisture under the conditions of use, so it is susceptible to static electricity. It is possible to suppress the generation of dust, and there is no adhesion of dust due to static electricity, so it is suitable from this point of view as well.
Also from this point of view, the ethylene content is more preferably 50 mol% or less. Furthermore, the EVOH film used in the present invention has a higher plasticizer resistance, better plasticizer resistance, migration, and exudation properties, and is one of the more excellent embodiments that can further improve the water resistance of the surface of the film. A preferred embodiment is a composite structure consisting of an EVOH layer with an ethylene content and an EVOH layer with a lower ethylene content. i.e. compound
On the surface of the EVOH film, adjacent to the adhesive layer, EVOH with an ethylene content of 20 to 35 mol%, which has better plasticizer resistance, etc., is used, and on the outer surface, ethylene 40 to 60%, which has a better water resistance, is used. mole%
An embodiment in which EVOH is arranged is more preferable.
The two-layer EVOH film is different from the above.
Two films of EVOH may be laminated and used, but in particular, the two different types of EVOH may be co-extruded using a two-layer die, or the two types of EVOH may be molten inside the die or outside the die. A composite material with different characteristics on the front and back surfaces obtained by integrating the EVOH resin flows of
EVOH film is more preferably used. In this case, no adhesive resin is required between the two types of EVOH layers, which is also more preferable.

EVOH has extremely good plasticizer resistance, so even if it is thin, it will still be effective.
When the thickness reaches the extremely thin region shown below, damage such as scratches is likely to occur, and on the other hand, with abnormal melt deposition operations, technical difficulties increase when obtaining a pinhole-free film, resulting in rejected products. This is not desirable. In addition, embossing is often applied due to the need for appearance, suppression of gloss, embossing of patterns, etc. In this case, the thickness of the EVOH film is preferably at least 5μ or more. . Furthermore, if the EVOH film exceeds 50μ, it is not only economically disadvantageous, but also has the characteristics of soft polyvinyl chloride sheets, etc.
This is undesirable because it affects the properties of the material to be heat laminated, such as impairing its flexibility. 40μ
The following are more preferred.

The EVOH film may be in an unstretched and unheat-treated state, but it is more preferably heat-treated from the viewpoint of dimensional stability, water resistance, etc.
EVOH film has superior embossability compared to other resins, and the thermal lamination film of the present invention is often suitably used after being laminated and then embossed. In such a case, an unstretched EVOH film is more suitable. Further, when higher water resistance is required, it is more preferable to use at least uniaxially stretched, especially biaxially float stretched. In this case, the stretching ratio is 1.5 times or more in the case of uniaxial stretching, and the area magnification is 3 times or more in the case of biaxial stretching, more preferably 5 times.
It is more preferable that the amount is more than double that.

As mentioned above, the thermal lamination film of the present invention is most suitably used as a thermal lamination film for plasticized polyvinyl chloride film sheets, but it also has good adhesion to substrates made of paper, such as wallpaper. Therefore, it can be suitably used as a coating material for paper substrates or products as it can provide excellent surface stain resistance, ability to wipe off the stain, and excellent embossing properties of the EVOH layer. can.

Next, the present invention will be explained with reference to examples, but the scope of the present invention is not limited.

Example 1 A 15μ thick film (unstretched film) of EVOH with an ethylene content of 31 mol% and a saponification degree of vinyl acetate component of 99.2% was coated with a gravure coater using a urethane adhesive AD-335A and a hardening agent Cat-10.
(manufactured by Toyo Morton Co., Ltd. Mixing ratio 17:1. Belongs to the above B) and maleic anhydride 1 mol% modified vinyl chloride
86 mol%-vinyl acetate 13 mol% copolymer adhesive
MPR-TM (manufactured by Nissin Chemical Co., Ltd.; belongs to A above)
Using a solution of 20% by weight toluene/methyl-ethyl ketone (weight ratio) = 1/2 of an adhesive consisting of a mixing ratio (weight) of A/B = 65/35, the coating amount was 2 g/m ²
(based on solid content) and at a temperature of 110
℃ for 1 minute. In order to examine the blocking properties of the obtained coated film, the coated film and the uncoated EVOH film were brought into close contact with each other under a pressure of 50 g/cm ² , and whether the adhesion after standing for 24 hours would be a practical obstacle. I looked into it. No stickiness,
It was confirmed that there were no problems with blocking properties. The coated film also had good slip properties. The obtained coated EVOH film
Di-2-ethylhexyl phthalate after 50 days
The material was laminated onto the surface of a 0.3 mm soft polyvinyl chloride sheet containing 38% by weight at a temperature of 150° C. using a thermal lamination method. The adhesive strength was measured by T-peel, and it was confirmed that the soft polyvinyl chloride layer was destroyed and had sufficient adhesive strength. An unplasticized hard polyvinyl chloride plate (6 cm x 6 cm, thickness 2 mm) is placed in close contact with the EVOH side of the soft polyvinyl chloride sheet covered with the above EVOH film, and a load of 2 kg is applied to the hard polyvinyl chloride plate. The amount of exudation and migration of the plasticizer was measured at a temperature of 70°C.
It was investigated under the following conditions. Even after 50 hours, no increase in the weight of the rigid PVC board was observed.
No stickiness was observed on the surface of the EVOH layer, and oozing and migration of the plasticizer was completely prevented. Even if you wipe it with a wet cloth, the surface will not be damaged.
It showed sufficient water resistance.

For comparison, 86 mol% methyl methacrylate;
A sheet obtained by thermally laminating a film of the same thickness of an acrylic copolymer containing 14 mol % of butyl methacrylate to the flexible polyvinyl chloride sheet was similarly subjected to the test. The weight change of the hard polyvinyl chloride plate after 24 hours was 3.2% by weight. It was confirmed that the weight change was caused by the transfer of the plasticizer, and stickiness on the surface of the copolymer film was also observed.

For comparison, AD-335A hardener Cat-10
(Mixing ratio 17:1) or MPR-TM alone as adhesive, adhesive coat as described above.
Got EVOH film. AD-335A and hardener Cat
-10, in which a urethane adhesive was used alone, caused significant blocking and was difficult to put into practical use. The slip property was also unsatisfactory. Also MPR−
The product using TM alone was satisfactory in terms of blocking resistance and slip property, but the adhesive strength after heat lamination was unsatisfactory as the EVOH layer peeled off at 0.28 kg/15 mm.

Example 2 Using the EVOH film in Example 1 with an ethylene content of 43 mol% and a saponification degree of vinyl acetate component of 99.3 mol%, the EVOH film for thermal lamination was obtained and thermal lamination was performed at a temperature of 130°C. The procedure of Example 1 was followed except for the test, and the exudation/transfer test of the plasticizer was conducted in the same manner. The film for thermal lamination exhibited good blocking resistance and good slip properties. No change in weight of the hard polyvinyl chloride board was observed. Moreover, the interlayer adhesive strength was sufficient, and when the adhesive strength was measured by T-peel, the soft polyvinyl chloride layer was destroyed. The water resistance of the EVOH surface was also sufficient.

Example 3 Ethylene content 26 mol%, saponification degree of vinyl acetate
99.5% EVOH(X) and ethylene content 51 mol%,
EVOH (Y) with saponification degree of 99.3% of vinyl acetate component
and are fed to two extruders, and using a two-layer T-die, the molten resin is joined in the die at 220℃,
A composite EVOH film was obtained in which the EVOH (X) layer had a thickness of 6 μm and the EVOH (Y) layer had a thickness of 9 μm. the compound
The EVOH film was thermally laminated in accordance with Example 1 so that the X side was adjacent to the soft polyvinyl chloride sheet. However, the adhesives used were urethane adhesive EPS-703A, catalyst KP-90 (manufactured by Dainippon Ink Co., Ltd., mixing ratio 10:1, belonging to B above), and MPR-TM used in Example 1 at a mixing ratio of A/ B=1
For the flexible polyvinyl chloride sheet, di-n-octyl phthalate/tri-2-ethylhexyl phosphate was used as a plasticizer.
Thermal lamination was performed at a temperature of 125° C. using a flexible polyvinyl chloride sheet containing 35% by weight of a 50/50 (weight ratio) mixture.

The EVOH film coated with the adhesive layer showed good blocking resistance and also good slip resistance. The soft polyvinyl chloride sheet on which the EVOH film was thermally laminated was examined in the same manner as in Example 1 to see if the plasticizer oozed out or migrated. Neither the weight change nor the surface stickiness was observed. The adhesive strength between the layers was also sufficient, and when the adhesive strength was measured by T-peel, the polyvinyl chloride layer was destroyed.

For comparison, a flexible polyvinyl chloride sheet obtained by thermally laminating the acrylic copolymer film used in Example 1 was obtained and subjected to the same test to determine the presence or absence of oozing and migration. The weight increase of the rigid polyvinyl chloride board was 3.1% by weight after 30 hours.

For comparison, EPS-703 and catalyst KP-90 (mixing ratio 15:1) were used alone as an adhesive to obtain a coated EVOH coated with the adhesive layer, but the blocking resistance and slipping resistance were Both were defective and could not be put into practical use.

Example 4 Using the biaxially stretched (area stretching ratio 3 x 3 times) EVOH film with an ethylene content of 49 mol% and a saponification degree of vinyl acetate component of 99.2% in Example 1,
In addition, as a soft polyvinyl chloride sheet, plasticizer chlorinated paraffin/di-n-octyl phthalate =
The sheet containing 39% by weight of a 50/50 (weight ratio) mixture was also used as an adhesive, urethane adhesive AD.
-900, curing agent AD-RT5 (manufactured by Toyo Morton Co., Ltd., mixing ratio 100:15, belongs to B above) and MPR-TM
Example 1 was carried out in the same manner as in Example 1, except that a 50/50 (weight ratio) mixed adhesive was used. No change in the weight of the hard polyvinyl chloride plate nor any oozing of the plasticizer onto the surface of the EVOH film was observed. The adhesion between the layers was sufficient and the polyvinyl chloride image was destroyed when the adhesion was measured by T-peel. Applicable
The water resistance of the EVOH surface was also sufficient.

In the case of a film made of the same acrylic copolymer as in Example 1 used for comparison, the weight change was 3.1% by weight, and stickiness on the surface of the film was also observed.

For comparison, AD-900 and hardening agent AD-RT5
An EVOH film coated with the adhesive layer was obtained by using a urethane adhesive alone as an adhesive, but the adhesive strength was sufficiently satisfactory (the polyvinyl chloride layer was destroyed). The blocking resistance was extremely unsatisfactory and could not be put to practical use.

Example 5 In Example 1, a mixture (mixing ratio (weight)
1:2) was used in the same manner as in Example 1. The film for thermal lamination exhibited good anti-blocking properties and good slip properties. No change in weight of the hard polyvinyl chloride board was observed. Further, the interlayer adhesive strength was sufficient, and when the adhesive strength was measured by T-peel, the soft polyvinyl chloride layer was destroyed. The water resistance of the EVOH surface during cleaning was also sufficient.

Example 6 In Example 1, the vinyl chloride adhesive contained 80 mol% of the vinyl chloride component, 17 mol% of the vinyl acetate component,
A film for thermal lamination obtained in the same manner as in Example 1 except that a copolymer containing 3 mol % of the ethyl actylic acid ester component was used showed good blocking resistance and good slip property. No change in weight of the hard polyvinyl chloride board was observed. Further, the interlayer adhesive strength was sufficient, and when the adhesive strength was measured by T-peel, the soft polyvinyl chloride layer was destroyed.

Claims (1)

[Scope of Claims] 1. A vinyl chloride copolymer (A) in which one of its surfaces contains 60 to 99 mol% of vinyl chloride component and 40 to 1 mol% of vinyl acetate and/or (meth)acrylic acid ester component. and a reactive polyurethane polymer (B) containing an isocyanate group, the adhesive layer having an ethylene content of 20 to 60 and covered with an adhesive layer having a mixing ratio (weight) of A/B = 2/3 to 6. A film for thermal lamination comprising a saponified ethylene-vinyl acetate copolymer having a saponification degree of vinyl acetate component of 95% or more by mole. 2. The film according to claim 1, having an ethylene content of 25 to 50 mol%. 3. Claim 1, wherein the saponified ethylene-vinyl acetate copolymer film has a thickness of 5 to 50μ.
The film according to item 1 or 2. 4 The ethylene-vinyl acetate copolymer saponified film has two saponified layers, one having an ethylene content of 20 to 35 mol% and the other having an ethylene content of 40 to 60 mol%.
4. A film according to any one of claims 1 to 3, comprising a layer, the former being adjacent to the adhesive layer. 5. The film according to any one of claims 1 to 4, which is used for thermal lamination to a plasticized polyvinyl chloride film or sheet.