JP2010163579A - Adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition which is excellent in the storage stability and initial adhesion strength of a composition and is particularly excellent in hot saline water-resistant adhesiveness, in the adhesion of polyolefin and metal. <P>SOLUTION: The adhesive composition includes an acid-modified polyolefin resin dispersion (A) and a compound (B) containing an S (sulfur) element. In the adhesive composition, the content of the S (sulfur) element is 1 to 10 wt.% of the solids of the adhesive composition. Preferably, the compound (B) containing an S (sulfur) element is an epoxy resin (C). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adhesive composition used for bonding a polyolefin and a metal.

Conventionally, so-called polyvinyl chloride, which is made by coating or laminating a vinyl chloride resin (hereinafter also simply referred to as a vinyl chloride resin) on the surface of a steel sheet for home appliance outer panels, building interior materials, furniture materials, etc. Steel plates have been used. The vinyl chloride resin used in these PVC steel sheets shows good processability and durability due to the compounding prescription, is easy to color, etc., and is excellent in cosmetics. In addition, it is inexpensive and widely used in various fields. Has been.
However, environmental problems have been greatly highlighted in recent years, and some of the dioxins that are thought to be generated during the incineration of phthalate plasticizers and PVC resins in PVC resins are chemical substances (environmental hormones) that are suspected of causing endocrine disruption. ) Is listed.
For this reason, various polyolefin resins have been proposed as alternatives to such vinyl chloride resins. Polyolefin resins are non-toxic, have strong resistance to acids, alkalis, organic solvents, etc., are excellent in mechanical strength and wear resistance, and are inexpensive. It is being used for interior materials and furniture materials. However, since the polyolefin resin is non-polar, it is difficult to adhere to a metal.

Conventionally, various adhesives, paints, primers, etc. have been proposed for bonding between such polyolefin resins and metals (steel plates for home appliances, interior materials for building structures, steel sheets used for furniture materials, etc.). . Typical examples are thermosetting resins such as epoxy resins, phenol resins, melamine resins, polyurethane resins, polyester resins, polyamide resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, etc. A base adhesive or paint obtained by dissolving a resin or a thermoplastic resin in an organic solvent was mixed with a solvent-dispersed modified polyolefin resin. That is, the thermosetting or thermoplastic resin is used to adhere to the metal part, and the modified polyolefin resin is used to adhere to the polyolefin. (Patent Documents 1 and 2)
However, although these adhesives can obtain a certain level of adhesiveness, they cannot be said to have sufficient adhesiveness in applications where severe processing is performed. Laminated steel sheet manufacturers are increasing the level of customer demand and performing an Ericksen test after boiling (see JIS K6744 (1992)) and a salt warm water test as internal tests. For the Erichsen test, a composition comprising an acid-modified polyolefin resin solvent dispersion and an epoxy resin was added to 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene and their derivatives as new components. Improvement was seen by adding at least one selected from the group consisting of: (Patent Document 3)
However, it is difficult to say that the adhesive sufficiently satisfies the required characteristic (adhesion after the salt warm water test) that does not cause peeling after the salt warm water test, which is a more severe condition.

JP 47-131972 A Japanese Patent Publication No. 7-68502 JP 2003-261847 A

    The present invention provides an adhesive composition having good adhesion to both metals and polyolefin resins, excellent in storage stability and initial adhesive strength of the composition, particularly excellent in salt-warm water resistance, and using the same It is providing the polyolefin laminated steel plate and polyolefin metal adhesion structure which become.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research and found that there is an adhesive composition containing an acid-modified polyolefin resin dispersion (A) and a compound (B) containing an S (sulfur) element. Invented. That is,
[1] An adhesive composition comprising an acid-modified polyolefin resin dispersion (A) and a compound (B) containing an S (sulfur) element.
[2] The adhesive composition according to [1], wherein the S element content is 1 to 10% by weight in the solid content of the adhesive composition.
[3] The adhesive composition according to [1] or [2], wherein the compound (B) containing an S element is an epoxy resin (C).
[4] The adhesive composition according to [3], wherein the epoxy resin (C) is 50 to 1000 parts by weight with respect to 100 parts by weight in terms of solid content of the acid-modified polyolefin resin solvent dispersion (A).
[5] The adhesive composition according to [3], wherein the epoxy resin (C) is a polysulfide-modified epoxy resin.
[6] The adhesive composition according to [1], further including an epoxy resin (D) other than the epoxy resin (C) containing an S element.
[7] The adhesive composition according to [6], wherein the epoxy resin (D) is a bisphenol A type epoxy resin.
[8] The adhesive composition according to [8], wherein the adhesive composition is dissolved or dispersed in an organic solvent.
[9] A polyolefin / metal bonded structure obtained by bonding a metal and a polyolefin resin using the adhesive composition according to [1].
[10] A polyolefin-laminated steel sheet obtained by laminating and bonding a steel sheet and a polyolefin resin film or sheet using the adhesive composition according to [1].
Here, S (sulfur) means a sulfur element.

  INDUSTRIAL APPLICABILITY The present invention is an adhesive composition excellent in storage stability and initial adhesive strength of a composition in bonding polyolefin and metal, and particularly excellent in salt-and-warm water resistance, and useful for various adhesives and heat sealants. .

The present invention will be described in detail below.
The present invention is an adhesive composition comprising an acid-modified polyolefin resin dispersion (A) and a compound (B) containing an S element. Content of S element is 1-10 normally in solid content of this composition, Preferably it is 2-7, More preferably, it is 4-6 weight%. If content of S element is the said range, it is preferable at the point of salt hot water adhesiveness.
In addition, content of S element in this invention is the elemental analysis measured using DX-500 by Dionex company by the ion chromatograph method.

[Acid-modified polyolefin resin solvent dispersion (A)]
The acid-modified polyolefin resin solvent dispersion (A) used in the present invention is obtained by dispersing an acid-modified polyolefin resin in a solvent. Polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, etc., ethylene or α-olefin homopolymers containing 3 to 20 carbon atoms, α containing ethylene and carbon atoms 3 to 20 -The copolymer with an olefin, the copolymer of the alpha olefin containing 3-20 carbon atoms of 2 or more types, etc. are mentioned.

Examples of the unsaturated dicarboxylic acid anhydride include maleic anhydride, hymic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic acid anhydride, and bicyclocarboxylic acid. [2.2.2] Oct-5-ene-2,3-dicarboxylic acid anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic acid anhydride 2-octa-1,3-diketospiro [4.4] non-7-ene, bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid anhydride, tetrahydrophthalic acid anhydride, x-methyl-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic anhydride, x-methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, norborn-5 En-2,3-Zika , And the like Bon anhydride.
Among the unsaturated dicarboxylic anhydrides, maleic anhydride or hymic anhydride is particularly preferable. Of course, ring opening products of these unsaturated dicarboxylic acid anhydrides can also be used if necessary. Further, two or more of the unsaturated carboxylic acid anhydrides may be used in combination, or a ring-opened product of the unsaturated dicarboxylic acid anhydride and the unsaturated dicarboxylic acid anhydride may be used in combination.

The organic solvent for dissolving or dispersing the acid-modified polyolefin resin and the epoxy resin described below is not particularly limited, and examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene, hexane, heptane, octane, decane. Aliphatic hydrocarbons such as cyclohexane, cyclohexene, alicyclic hydrocarbons such as methylcyclohexane, ethylcyclohexane, alcohols such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, Ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cellsolves such as methyl cellosolve, ethyl cellosolve, methyl acetate, acetic acid Butyl chill acetate, methyl propionate, and butyl formate, trichlorethylene, dichloroethylene, and halogenated hydrocarbons such as chlorobenzene.
Among these, aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons are preferable.
The particle shape of the acid-modified polyolefin resin in a dispersed state is generally and preferably spherical, but is not necessarily spherical. The average particle size of the particles (measuring device: Multisizer 3 Coulter Counter) is usually 1 to 20 μ, preferably 5 to 15 μ. Moreover, the non volatile matter (solid content concentration) in a dispersion is 5 to 40 weight% normally.

[Compound containing element S (B)]
Examples of the compound (B) containing an S element of the present invention include a thiol resin, a sulfur resin, a polysulfide polymer, and an epoxy resin containing an S element.
Among these, a polysulfide polymer and an epoxy resin containing an S element are preferable, and an epoxy resin containing an S element is more preferable.

Epoxy resin containing element S (C)
Examples of the epoxy resin (C) containing S element include polysulfide-modified epoxy resins having a polysulfide skeleton (-SS-) in the main chain, such as FLEP-50 and FLEP-60 (manufactured by Toray Fine Chemical Co., Ltd.). Can do. From the viewpoint of metal adhesion and corrosion resistance, polysulfide-modified epoxy resins are preferred.
The epoxy equivalent of (C) is usually 200 to 4000, preferably 200 to 1000, and more preferably 200 to 500, from the viewpoint of salt warm water adhesiveness. Further, (C) contributes to the improvement of corrosion resistance, in particular, salt hot water adhesion.

The amount ratio of the acid-modified polyolefin-based resin solvent dispersion (A) and the epoxy resin (C) is in terms of initial adhesive strength and corrosion resistance, with respect to 100 parts by weight in terms of solid content of the component (A), The epoxy resin component is usually 50 to 1000, preferably 100 to 700, and more preferably 150 to 400 parts by weight.
In the present invention, an epoxy resin (D) other than the epoxy resin (C) containing an S element can be further suitably used. Examples of the epoxy resin (D) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional epoxy resin, flexible epoxy resin, brominated epoxy resin, glycidyl ester type epoxy resin, polymer type epoxy resin, and biphenyl. A type epoxy resin or the like can be used. Among these, bisphenol A type epoxy resins are preferable in terms of improving the initial adhesive strength.
The molecular weight of the bisphenol A type epoxy resin is 10,000 to 50,000, preferably 30,000 to 50,000 in terms of initial adhesive strength.

Moreover, the ratio of the epoxy resin (C) containing S element and the other epoxy resin (D) is the balance of physical properties, and (D) is usually 50 to 100 parts by weight of (C). 400, preferably 50 to 200, more preferably 50 to 150 parts by weight.
The adhesive composition of the present invention is preferably dissolved or dispersed in a solvent. Water or an organic solvent is raised as the solvent. The amount of the solvent is usually 500 to 1000 parts by weight with respect to 100 parts by weight in terms of solid content of all components. Examples of the organic solvent to be used include those described above.
The adhesive composition of the present invention can be obtained by mixing the above components (A) to (D) at room temperature or by crystallization (heating dissolution and cooling) after mixing.

The present invention is a polyolefin / metal bonded structure using the adhesive composition of the present invention.
Moreover, this invention is a polyolefin laminated steel plate formed by laminating | bonding the steel plate and the polyolefin resin film or sheet | seat using the adhesive composition of this invention.
These adhesive structures are manufactured by applying an adhesive resin to the steel sheet surface, baking and drying the adhesive resin, and then continuously applying a polyolefin film on the upper surface while the adhesive resin layer is in a molten state. Laminate and adhere.
The adhesive composition of the present invention is excellent in initial adhesive strength and low-temperature storage stability, and is particularly excellent in salt-resistant hot water adhesiveness, and therefore can be suitably used for ships, automobile parts and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention more concretely, this invention is not limited to these Examples.

[Coating, baking, bonding process]
Bar coater No. on the surface of a stainless steel substrate (SUS430 No. 4). 12 applied the sample solution. After drying the solvent, baking was performed at 200 ° C. for 60 seconds. Only the upper part of the heat sealer is heated, and a stainless steel substrate is laminated on the PP sheet or TPO sheet having a thickness of 300 μm and a width of 25 mm, and the heat seal is performed at 200 ° C., 1 kg / cm 2, for 1 second. It was.

[Adhesion: Measurement of peel strength]
Using an autograph manufactured by Shimadzu, peeling was performed at a peeling angle of 180 ° and a peeling speed of 100 mm / min. The peel strength of the heat-sealed sample was measured, and the average value of 3 points was obtained.

[Evaluation of storage stability]
After the prepared sample was stored at 0 ° C. for 30 days, the state of the solution (solidification, presence or absence of gelation, etc.) was confirmed.

[Salt-resistant hot water adhesion]
The bonded PP sheet / stainless steel substrate was immersed in 5 wt%, 50 ° C. salt water. Adhesiveness was evaluated from the presence or absence of peeling after immersion.

[Example 1]
Unistor R-200A (manufactured by Mitsui Chemicals; solid content 25%) as the acid-modified polyolefin resin solvent dispersion (A), FLEP50 (manufactured by Toray Fine Chemical Co., Ltd.) as the epoxy resin (C) containing S element, As the epoxy resin (D), EXA-123 (manufactured by DIC Corporation), which is a bisphenol A type epoxy resin, was used.

The compound (B) / bisphenol A type epoxy resin containing the acid-modified polyolefin resin solvent dispersion (A) / S (sulfur) element was mixed at a weight ratio of 30/35/35 at room temperature. Application, baking and adhesion were carried out by the above-described methods, and peel strength was measured and a salt warm water adhesion test was conducted. The results are shown in Table 2.
In addition, the content measured using ion-chromatography method of S element of this example using DX-500 made from Dionex was 0.51 wt%, and the calculated value was 0.49 wt%.

[Examples 2 to 5]
The same compounds as in Example 1 were used and mixed in the proportions shown in Table 1. Moreover, application | coating, baking, and adhesion | attachment were performed by the method similar to Example 1, and the peeling strength measurement and the salt-warm water-resistant adhesion test were done.
The results are shown in Table 2.

[Comparative Example 1]
The same compounds as in Example 1 were used and mixed in the proportions shown in Table 1. Moreover, application | coating, baking, and adhesion | attachment were performed by the method similar to Example 1, and the peeling strength measurement and the salt-warm water-resistant adhesion test were done.
The results are shown in Table 2.

Claims (10)

An adhesive composition comprising an acid-modified polyolefin resin dispersion (A) and a compound (B) containing an S (sulfur) element. The adhesive composition according to claim 1, wherein the S element content is 1 to 10% by weight in the solid content of the adhesive composition. The adhesive composition according to claim 1 or 2, wherein the compound (B) containing an S element is an epoxy resin (C). The adhesive composition according to claim 3, wherein the epoxy resin (C) is 50 to 1000 parts by weight with respect to 100 parts by weight in terms of solid content of the acid-modified polyolefin resin solvent dispersion (A). The adhesive composition according to claim 3, wherein the epoxy resin (C) is a polysulfide-modified epoxy resin. Furthermore, the adhesive composition of Claim 1 containing epoxy resins (D) other than the epoxy resin (C) containing S element. The adhesive composition according to claim 6, wherein the epoxy resin (D) is a bisphenol A type epoxy resin. The adhesive composition according to claim 1, wherein the adhesive composition is dissolved or dispersed in an organic solvent. A polyolefin / metal bonded structure obtained by bonding a metal and a polyolefin-based resin using the adhesive composition according to claim 1. A polyolefin-laminated steel sheet obtained by laminating and bonding a steel sheet and a polyolefin resin film or sheet using the adhesive composition according to claim 1.