JPH0621209B2 - Resin composition for adhesive or film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition. More about metal,
The present invention relates to a resin composition suitable for use as an adhesive with wood, paper, polyolefin and the like, and also used as a film and having excellent gas barrier properties. Conventionally, various resin compositions suitable for adhesives have been developed, and there are advantages and disadvantages, and the present situation is that they are properly used depending on the application.

The present inventors have earnestly studied to obtain an adhesive having an adhesive force at a relatively low temperature and a high adhesive force in a wide temperature range, and as a result, arrived at the resin composition of the present invention.

That is, the gist of the present invention is that the component (A) is a polyvinyl acetal resin of 5 to 98% by weight, and the component (B) is α, β.
Modified polyethylene resin or modified polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride 2 to
The resin composition for adhesives or films comprises 95% by weight and optionally 50% by weight or less of a plasticizer as the component (C) with respect to the component (A).

It is well known that the component (A), such as polyvinyl formal resin and polyvinyl butyral resin, is used as a component of an adhesive to a metal, but these have strong crosslinkability, for example, they are heated and melted alone to form a sheet. Cannot be used as a bonding layer or can be melted by heating and used for lining by extrusion molding or the like because of the crosslinking property. Therefore, these resins are generally used by dissolving them in a solvent. In some cases, a large amount of plasticizer is added to prevent cross-linking and it is used in a molten state. Generally, however, when a large amount of plasticizer is added, the plasticizer bleeds on the adhesive surface, that is, the interface between metal and resin. As a result, the adhesive strength also decreases with time. Further, for example, polyvinyl acetal resin has no adhesive force to polyolefin resin and is not suitable as an adhesive agent for adhering metal and polyolefin.

The modified polyethylene resin or modified polypropylene resin modified by the component (B) α, β unsaturated carboxylic acid or its acid anhydride has adhesiveness to the polyolefin if it is the polyolefin itself, and the modified polyolefin is particularly a metal. It is one of the adhesives useful as an adhesive to polyolefin resin and is particularly effective when lining molten resin, but the lining temperature is relatively high and the object to be bonded is preheated to near the melting temperature of the modified polyolefin. It has the drawbacks that it must be. In order to lower the lining temperature, it is conceivable to control the crystallinity of the resin. Although the lining temperature can be lowered at a certain temperature by this, there is a drawback that the adhesive strength is lowered when the laminate is exposed to a high temperature. The present inventors, as a result of studying the development of a more effective adhesive, a polyvinyl acetal resin as the component (A) and a modified polyethylene resin modified with an α, β unsaturated carboxylic acid or its acid anhydride as the component (B). Alternatively, the present invention has been found out that a composition containing a modified polypropylene resin as a necessary component and a plasticizer added thereto is effective as an adhesive used by heating and melting at a relatively low temperature.

The reason why the composition of the present invention is suitable as an adhesive used by heating and melting at a relatively low temperature is considered that the composition of the present invention does not cause crosslinking even when the polyvinyl formal resin is in a heating and melting state. . The reason for this is not clear, but it is considered that the polyolefin prevents the polyvinyl formal resin from crosslinking.

Such a phenomenon, that is, the phenomenon in which the polyolefin reduces the cross-linking of polyvinyl formal was unexpected, and the industrial benefit is very large.

The component (A) used in the present invention, that is, a polyvinyl acetal resin is generally produced by polymerizing a vinyl acetate monomer to produce a polyvinyl acetate resin, and then reacting the polyvinyl alcohol obtained by saponification with an aldehyde. . That is, the polyvinyl acetal resin is a resin having a vinyl acetal group, a vinyl alcohol group, and a vinyl acetate group, the reaction product with formaldehyde is a polyvinyl formal resin, and the reaction product with butyraldehyde is called a polyvinyl butyral resin. Examples of the polyvinyl acetal resin include polyvinyl acetoacetal and polyvinyl propyl acetal. Among them, polyvinyl butyral resin is preferably used.

Further, a polyvinyl acetal resin containing a carboxyl group is also preferably used.

Carboxyl groups are present in polyvinyl acetal resin in an amount of 0.1.
1 to 5 mol%, preferably about 0.2 to 3 mol% is desirable. As a polyvinyl acetal resin containing a carboxyl group, for example, by copolymerization of vinyl acetate and an unsaturated carboxylic acid, a method for producing a polyvinyl acetal resin by a conventional method, or an aldehyde containing a carboxyl group when acetalizing polyvinyl alcohol. It is obtained by reacting with.

The average degree of polymerization of the polyvinyl acetal resin used in the present invention is not particularly limited, but is preferably in the range of 300 to 5,000, more preferably 500 or more. The degree of acetalization is preferably about 50 to 88 mol%.

The modified polyethylene resin or the modified propylene resin used in the present invention is based on polyethylene or polypropylene, which has 0.97 to 0.91 g / cm ³ of high / medium / low density polyethylene, polypropylene homopolymer or propylene as a main component. And random or block copolymers, copolymers of ethylene and α-olefins having 3 to 10 carbon atoms and having a density of about 0.88 to 0.91 g / cm ³ , and the like. These may be used alone or in combination. Used.

The modified polyethylene resin or modified polypropylene resin of the present invention is the above-mentioned polyethylene or polypropylene in the presence of an organic peroxide, maleic acid, an ethylenically unsaturated carboxylic acid such as acrylic acid or an acid anhydride thereof (hereinafter referred to as “modifying agent”). It may be referred to as "). In order to mix modified polyethylene or modified polypropylene (hereinafter, simply referred to as modified polyolefin) to the polyvinyl alcohol resin, the modified polyolefin may be mixed as it is, but the modified polyolefin is mixed with the unmodified polyolefin and the polyvinyl acetal is used. It is desirable to mix it with the resin.

The compounding ratio of the modified polyolefin and the unmodified polyolefin is preferably 20 parts by weight or more based on 100 parts by weight of the total amount of both.

The amount of the modifier contained in the modified polyolefin or the blend of the modified polyolefin and the unmodified polyolefin is 30.
0 to 10,000 ppm, preferably 500 to 7,000
It is preferably 0 ppm. If it is less than 300 ppm, the adhesive strength is poor, and if it exceeds 10,000 ppm, gelled substances, color development, etc. occur, which is not preferable.

The composition ratio of the polyvinyl acetal resin {(A) component} and the polyolefin {(B) component} is 5 to 98% by weight of the (A) component,
The component (B) may be optionally mixed in the range of 95 to 2% by weight.

When the content of the component (A) is 5% by weight or less, it is not possible to lower the adhesive temperature, and when it is 98% by weight or more, there arises a problem in the adhesive strength in a high temperature region and the adhesive strength with polyolefin is poor.

Further, the composition of the present invention has a good gas barrier property and can be used for a film or the like which requires a gas barrier property. The gas barrier property is especially 70-97% by weight of the component (A)
Component (B) is 3 to 30% by weight, and in some cases 5 of component (A).
Compositions containing 0% by weight or less of component (C) are preferred.

If the amount of component (B) exceeds 30% by weight, the gas barrier property becomes poor.

Incidentally, 50% by weight or less of a plasticizer can be added to the component (A). Generally, the addition of a plasticizer is effective for lowering the adhesion temperature.

However, if it exceeds 50%, the adhesive strength is lowered, which is not preferable.

Examples of the plasticizer include phthalates such as dibutyl phthalate and dioctyl phthalate, phosphates such as tricresyl phosphate, dibutyl sebacate and di-
A fatty acid ester such as 2-ethylhexyl adipate or dibutyl succinate, or a glycol derivative such as triethylene glycol dibutyrate is generally used and can be arbitrarily selected from these. A filler may be added to improve the adhesive strength, and examples thereof include calcium carbonate, talc, mica, carbon graphite, and carbon black. The amount of filler added is 100 in total of the components (A) and (B).
10 to 100 parts by weight, preferably 20 to 5 parts by weight
It is about 0 parts by weight.

Regarding the mixing of the above components, it may be heated and mixed under general conditions with a mixing and dispersing machine such as a ribbon blender Banbury mixer, a kneader, a Henschel mixer, a roll, a single-screw or twin-screw extruder.

The heating temperature varies depending on the melting point of the resin used and the like, but is usually about 190 to 300 ° C, preferably 200 to 250 ° C.
Temperatures of the order of magnitude are used.

Hereinafter, the composition of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

In the examples and comparative examples, the peel strength is a value measured by a tensile tester manufactured by Toyo Baldwin at a tensile speed of 10 mm / min.

The oxygen gas permeability was measured according to ASTM-D-1434.

Example-1 Component (A): Polyvinyl butyral having a degree of polymerization of 1050 and a butyralization degree of 81%.

Component (B): Melt index (MI) (ASTM D1238-57
(Measured by T) 2.1 g / 10 minutes, density 0.931 g / cm ³ medium density polyethylene 100 parts by weight maleic anhydride (modifying agent) 0.36 parts by weight, α-α-bister butyl peroxy-paradiisopropyl MI 1.2g / 10 minutes, modifier graft obtained by blending 0.02 parts by weight of benzene and melt-extruding at a die temperature of 210 ° C. and a screw rotation speed of 50 rpm using a single screw extruder having a diameter of 30 mmφ and L / D24. Quantity 3
400ppm modified polyethylene.

55% by weight of component (A), 40% by weight of component (B) and di-2-ethylhexyl adipate 5 as component (plasticizer) 5
The weight percent was mixed with a ribbon blender (10 kg / batch) for 10 minutes.

Next, a twin-screw extruder with a diameter of 30mmφ (Ikegai Tekko, PCM30
-25 extruder) under the conditions of a die temperature of 210 ° C. and a screw rotation speed of 200 rpm (coaxial rotation) to melt and knead into pellets to obtain an adhesive composition.

Using a two-layer T-die equipped with a 30 mmφ extruder and a 55 mmφ extruder, the composition obtained above was passed through a 30 mmφ extruder, and as an outer layer, MI = 0.2 and a high density of 0.946 g / cm ³ . Polyethylene is fed from the extruder with a diameter of 55 mm to a die temperature of 24
50 ^W mm x 15 prepared by using a two-layer T-die set to 0 ° C to prepare a molten sheet and controlling it to a predetermined temperature (Table-1) in advance.
A two-layer molten sheet was placed on a 0 ^L mm × 3 ^t mm hot-rolled steel sheet so that the surfaces of the compositions were in contact with each other, and degassed by a roll to bond them to obtain a laminate.

The thickness of the sheet was 100 μm of the composition sheet and the outer layer polyethylene sheet was 3.4 mm.

A test piece was cut out from the laminate to a width of 2.5 cm and used as a measurement sample, and the peel strength at 20 ° C. was obtained. The results are shown in Table-1.

Example-2 70% by weight of the component (A) used in Example-1 and 30% by weight of the modified polyethylene used in Example-1 as the component (B)
Was mixed well and a laminate of steel plate-adhesive layer-polyethylene was prepared in the same manner as in Example-1, and peel strength was determined.
Summarized in.

Comparative Example-1 A steel sheet-adhesive layer-polyethylene was prepared in the same manner as in Example-1 except that the composition comprising 55 parts by weight of the component (A) used in Example-1 and 5 parts by weight of a plasticizer was used as the adhesive layer. A laminate was prepared and the peel strength was determined. The results are shown in Table-2.

Comparative Example-2 A laminate of steel sheet-adhesive layer-polyethylene was prepared in the same manner as in Example-1, except that only the component (B) used in Example-1 was used as the adhesive layer, and the peel strength was determined. Table of results
Shown in 2.

Example-3 27% by weight of the component (A) used in Example-1 and 40% by weight of the modified polyethylene used in Example-1 as the component (B)
And 30% by weight of unmodified polyethylene were used, and 3% by weight of dioctyl phthalate was used as a plasticizer, and a laminate of steel plate-adhesive layer-polyethylene was prepared in the same manner as in Example-1 to obtain peel strength. I asked. The results are shown in Table-2.

In Comparative Example-1, there is no adhesive force between the adhesive layer and the polyethylene layer, and peeling occurs at the interface between them, so that Comparative Example-2 and Example-
In No. 3, peeling occurs between the steel plate and the adhesive layer.

Comparative Example-2 shows high adhesive strength at 170 ° C. on the high temperature side, but 1
It lacks adhesive strength at low temperatures such as 30 ° C.

Example-4 Pellets of the adhesive composition used in Example-1 were made into a film having a thickness of 100 µm using an inflation device. Separately, a sheet having a thickness of 2 mm was produced from the unmodified polyethylene used in Example-1. A film made of an adhesive composition and a sheet made of unmodified polyethylene were placed on a steel plate and laminated by pressing at 180 ° C. The three adhered well.

Example-5 Component (A): A polyvinyl butyral resin having a polymerization degree of 980 and a butyralization degree of 70%.

(B) component: 0.26% grafted density of maleic anhydride
Modified low density polyethylene with 0.921 g / cm ³ and MI 1.9 g / 10 minutes.

Component (C) (plasticizer): dibutyl adipate.

(A) component (85% by weight), (B) component (10% by weight), (C) component (5% by weight) were mixed well, and then a 40 mmφ single phase extruder was used for 20
The mixture was kneaded, melted and pelletized at 0 ° C. Using the pellets, an inflation film having a thickness of 50 μm was formed. The film was a colorless transparent gel-free film. Using the same film, the oxygen gas permeability was determined and summarized in Table-3.

Comparative Example-3 A film was prepared in the same manner using only the modified low-density polyethylene used in Example-4, and the oxygen gas permeability was determined and summarized in Table-3.

Comparative Example-4 85 parts by weight of the polyvinyl butyral resin used in Example-4 and 5 parts by weight of the plasticizer were used and mixed well, and pelletized in the same manner as in Example-4. The pellets were considered to have a yellowish color and a change in resin. An inflation film was prepared using the pellet, but there was a large amount of gel, and holes were formed in the film around the gel portion, and a uniform film could not be formed.

Example-6 80% by weight of polyvinyl butyral resin having a degree of polymerization of 1100 and a degree of butyralization of 80%, a density of 0.948, 14% by weight of polyethylene having a melt index of 1.3, and 6% by weight of dioctyl phthalate as a plasticizer were well mixed. The pelletized film was formed in the same manner as in Example 4, and the oxygen gas permeability was determined and summarized in Table 3.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09J 123/26 JCL 7107-4J 129/14 JCV 6904-4J 151/06 JDH 7142-4J // B32B 27/32 8115-4F (72) Inventor, Seritoshi Suzuki, 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Kogyo Co., Ltd. (56) Reference JP-A-58-47037 (JP, A) JP-A-49- 38942 (JP, A) JP 49-13247 (JP, A) JP 48-32574 (JP, B1) JP 48-4090 (JP, B1) JP 43-1485 (JP, B1)

Claims (4)

[Claims] 1. A polyvinyl acetal resin of 5 to 98% by weight as the component (A), and a modified polyethylene resin or modified polypropylene resin 2 to 95 modified with an α, β unsaturated carboxylic acid or its acid anhydride as the component (B). % By weight, and optionally a plasticizer as component (C) is 50% by weight with respect to component (A).
A resin composition for an adhesive or a film, which comprises: 2. The resin composition according to claim 1, wherein the polyvinyl acetal resin is a polyvinyl butyral resin. 3. An α, β unsaturated carboxylic acid or an acid anhydride thereof is added to the modified polyethylene or modified polypropylene.
The resin composition according to claim 3, wherein the resin composition contains 100 to 10,000 ppm. 4. The component (A) is 70 to 97% by weight, and the component (B) is 3%.
The resin composition according to any one of claims 1 to 3, which comprises -30% by weight, and optionally 50% by weight or less of a plasticizer as the component (C) with respect to the component (A).