JPH0438583B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is characterized in that a polyolefin molded product and a polar dissimilar material are bonded together without any pretreatment or primer application on the surface of the polyolefin molded product.
It relates to composite products bonded via a new adhesive layer, and uses a large amount of polyolefin, especially polypropylene, and is used not only alone but in combination with other materials such as metals, such as automobiles, home appliances, and acoustics. Applies to equipment, etc. It can also be applied to laminated materials of polyolefin and metal plates such as steel plates and aluminum plates, which are used as corrosion-resistant or lightweight structural materials. [Prior Art] Polyolefin is non-polar and difficult to dissolve in solvents, making it difficult to bond. Although various adhesives are commercially available for adhering polyolefins to each other without using a primer, they are not effective for adhesion to metals such as iron and aluminum, glass, ceramics, and other polar dissimilar materials. In order to bond polyolefin and the above-mentioned polar dissimilar materials, the surface of the polyolefin molded product is modified by surface treatment using corona discharge, flame, plasma, etc., or by surface treatment with a mixture of chromic acid and sulfuric acid. A modified polyolefin modified by using a commercially available epoxy adhesive, cyanoacrylate adhesive, etc., or by adding a filler such as talc, wood flour, etc. to the polyolefin and/or an elastomer is used. The method used has been to apply a primer to the molded article and then apply a commercially available adhesive. Recently, instant adhesives that use a combination of a special primer and a special adhesive and can provide high adhesive strength even with unmodified polyolefin have become commercially available, but they are expensive. [Problems to be solved by the invention] In surface modification by pretreatment, corona discharge treatment has shape limitations, plasma treatment has size limitations, equipment is expensive, and flame treatment has dangers due to the use of fire. In addition to each having their own problems,
A common problem is that when foreign matter comes into contact with the surface to be treated, the activity is lost, making it difficult to handle the object. Chemical pretreatment involves the use of chemicals that cause pollution,
and require special treatment tanks. Special adhesives for polyolefins are expensive and require a primer coating process, which has cost constraints. As described above, when bonding a different polar material to a plastic, it is not advantageous to use polyolefin as the plastic even though the unit price of the resin is low. Therefore, polyolefins are not used for bonding plastics and dissimilar materials except when polyolefins are required due to physical properties. [Means for Solving the Problems] As a means for solving the above problems, the present inventors first used a common and inexpensive material as an adhesive raw material, and developed a method that can bond polypropylene and different materials without pretreatment. He invented an adhesive and an adhesive method as disclosed in Japanese Patent Application No. 61-242840, and also made inventions as disclosed in Japanese Patent Application No. 62-313903 and No. 63-91119. In other words, the invention of Japanese Patent Application No. 61-242840 shows that low chlorinated polypropylene exhibits adhesive properties to polypropylene, and highly chlorinated polyolefin and chlorinated rubber exhibit adhesive properties to polar dissimilar materials such as iron and aluminum. , a formulation based on chloroprene with the addition of low chlorinated polypropylene and highly chlorinated polyolefin and/or chlorinated rubber,
In addition to adhering both polypropylene and the dissimilar materials, the adhesive strength is higher than the adhesive strength shown in the case of mutual adhesion of each material, and furthermore, when drying by heating, when drying at room temperature It has been found that the adhesive strength is significantly increased compared to the conventional method. The invention of Japanese Patent Application No. 62-313903 is based on highly chlorinated substances.
It was discovered that it could be substituted with a phenolic resin that exhibits adhesive properties to metals and is compatible with chloroprene. In other words, it has been found that using only a highly chlorinated polypropylene without using a low chlorinated polypropylene results in a bond strength that can be put to practical use, although the adhesive strength is slightly lower. Orientation of chlorine atoms toward the metal surface is considered to be the reason why high adhesive strength is obtained when the adhesive compositions of these inventions are applied to bond polyolefin and metal. As a result of this orientation, the metal side of the adhesive has a higher chlorine atom density, while the opposite polyolefin side becomes more nonpolar, which is thought to increase affinity with polyolefin. These inventions are based on solvent-based adhesive compositions using chloroprene as a base material. However, in terms of working environment and workability, there is a greater need for hot-melt adhesives than solvent-based adhesives, so the present inventors , attempted to apply the above reasoning of the adhesion mechanism to hot-melt adhesives. In other words, instead of chloroprene, we applied a composition consisting of various thermoplastic elastomers and tackifiers used in hot melt adhesives.As a result of various studies, we developed a special combination of chlorinated polyolefin, tackifier, and elastomer. The present invention was completed based on the discovery that the effects thought to be due to the above-mentioned orientation were observed and high adhesive strength could be obtained. The present inventor selected an ethylene/vinyl acetate copolymer with a high vinyl acetate content, which has good compatibility with polar substances such as chlorinated polyolefin, as the elastomer for a hot melt adhesive, and combined this with an adhesive As a result of detailed studies using toluene solutions of tackifiers and chlorinated polyolefins, we found that modified rosins and phenolic resins are preferred as tackifiers, and among these, rosin-glycerin esters and rosin-modified phenolic resins are preferred. It has been found that this is particularly preferable. It has also been found that the chlorinated polyolefin is preferably a low chlorinated polypropylene having a chlorine content of 45% by weight or less, unlike when chloroprene is used as the base material. That is, the present invention is characterized in that a polyolefin resin and a different material having polarity are bonded to each other via an adhesive layer containing a composition consisting of at least the following A and B, or a combination of A, B, and C. The gist of this is to A: Chlorinated polypropylene with a chlorine content of 10 to 45% by weight B: Ethylene/vinyl acetate copolymer with a vinyl acetate group of 30 to 50% by weight C: One or more selected from the group consisting of modified rosin and phenolic resin Mixture of Two or More Components Furthermore, the adhesive layer is characterized in that the component A is 1 to 70% by weight of the total amount, and B/(B+C) is 20 to 100% by weight. Further, the above-mentioned component C is characterized in that it is either a rosin/glycerin ester or a rosin-modified phenolic resin. [Function] In order to bond a polyolefin resin molded product to a different polar material, conventional methods require degreasing of the polyolefin side, as well as physicochemical pretreatment and application of a special primer. However, when the composition of the present invention is used as an adhesive layer, no pretreatment other than degreasing is required; a solution of the adhesive layer composition of the present invention in a solvent such as toluene is applied to the adhered surface, and after drying, The adhesive layer is melted by stacking the surfaces to be adhered and heated, or the composition obtained by mixing and melt-kneading each component of the adhesive layer composition is melted and applied to the surface to be adhered. Accordingly, the preferred composition has a tensile shear strength of 55-65 Kg/ ^cm2 , 8-65 Kg/cm2,
A peel strength of 10Kg/25mm can be obtained. This will be explained in more detail below. Polyolefin resins to which the present invention is applied include polypropylene homopolymers, copolymers of propylene and ethylene or other α-olefins,
It is a high-density polyethylene homopolymer or a copolymer of ethylene and α-olefin with a density of 0.95 or more, and also includes composite materials in which organic or inorganic fillers are added. The polar dissimilar materials include metal materials such as iron, aluminum, and copper, ceramics such as glass and ceramics, natural materials and synthetic materials having hydroxyl groups, amino groups, or amide bonds. In the present invention, the reason why the chlorine content of the chlorinated polypropylene as component A is set to 10 to 45% by weight is that when the composition consisting of B and C of the present invention is used as a base, the highly chlorinated polypropylene is This is because the adhesiveness is not sufficient. Furthermore, those having extremely low chlorine content are not preferred because they have poor compatibility with other component resins. A particularly preferred range is 24 to 35% by weight. Even a small amount of the low chlorinated polypropylene as component A can improve the adhesion of the base resin to the polyolefin surface with respect to the total amount of the adhesive layer composition, but the preferred amount is 1 to 70% by weight. If the amount is too high, the peel strength will be significantly reduced. If the vinyl acetate group content of the ethylene/vinyl acetate copolymer, which is the B component of the present invention, is less than 30% by weight, it is undesirable due to poor compatibility with chlorinated polypropylene, and if it is more than 50% by weight, the adhesive group content is less than 30% by weight. Does not exhibit physical properties that can withstand use as a material. In addition, the modified rosin and phenolic resin listed as the tackifier, which is component C, are:
Esters of abietic acid, a rosin component, P
-Alkylphenol resins, terpene phenol resins, terpene bisphenol resins, rosin-modified phenol resins, etc., and particularly preferred are rosin-glycerin esters or rosin-modified phenol resins. Note that even without adding the tackifier (component C), that is, even when B/(B+C) is 100%, the low chlorinated polypropylene exhibits adhesive effects on both adherends, and has adhesive strength that is sufficient for practical use. However, the addition of a tackifier further increases the adhesive strength and also reduces the viscosity when melted or the viscosity of the solution when applied in a solvent form, improving workability. However, when the amount added is too large, that is, B/(B+
When C) is less than 20%, the viscoelasticity of the adhesive layer is reduced and the peel strength is significantly reduced. In the composition of the adhesive layer, an antioxidant may be added to prevent thermal deterioration during manufacturing, processing, and use of the adhesive, and waxes may be added to improve workability. [Effects of the Invention] As described above, the composite product of the present invention can be produced by combining a polyolefin resin molded product and a completely different molded product having polarity such as metal or glass without performing any pre-treatment or primer application. This was achieved by adhesion, which was previously considered to be extremely difficult.
Moreover, the materials used are not special products that are difficult to obtain.
It is a commercially available and easily available material, and since the adhesive layer can be formed in the form of a hot-melt adhesive that does not volatilize solvents, there is no need for equipment to improve the working environment, and it can be easily implemented anywhere. can. For the above reasons, the scope of application of the combination of a polyolefin resin molded product and a different material having polarity such as metal or glass is expanded, and it is extremely useful industrially. [Example] Preparation of adhesive sample (1) Adhesive layer forming method Example results A toluene solution (non-volatile component content: 25% by weight) containing the adhesive layer composition listed in each table as a non-volatile component was prepared as follows. Prepared with That is, the low chlorinated polypropylene (toluene solution) that is the A component is collected, diluted by adding a predetermined amount of toluene, and then the tackifier that is the C component is added and completely dissolved. Add the ethylene/vinyl acetate copolymer resin as component B, and leave to stand at room temperature for 24 hours or more, stir thoroughly, and then leave to stand at room temperature for 24 hours or more. The obtained solution is applied to the adhered part of the degreased test piece, and after drying at room temperature, the adhered parts are overlapped, and a piece of glass is applied to the back side of the adhered part on the resin side and fixed with a clip. Unless otherwise specified, this was heated at 150° C. for 5 minutes in a high-temperature bath of a thermal shock tester to melt the resin applied to the adhered portion and form an adhesive layer. The materials used in the table are as follows. A Note 1: Super Chron 803MW, manufactured by Sanyo Kokusaku Pulp Co., Ltd. (Chlorine content: 29.5% by weight) Note 2: Super Chron 822, manufactured by the same company (Chlorine content: 24.5 weight%) Note 3: Super Chron 804M, manufactured by the same company (Contains chlorine) Note 4: Super Chron 814H manufactured by the same company (chlorine content 43% by weight) B Note 1: Evaflex 45X manufactured by Mitsui Petrochemical Industries, Ltd. (vinyl acetate content 46% by weight) Note 2: manufactured by the same company Evaflex 150 (vinyl acetate content 33% by weight) C Note 1: Ester gum AAV (rosin glycerin ester) manufactured by Arakawa Chemical Co., Ltd. Note 2: Tamanol 510 (p-t-butylphenol resin) manufactured by the same company Note 3: Same as above Tamanol 145 (Rosin-modified phenolic resin) manufactured by Yasushi Kogyo Co., Ltd. Note 4: YS Polyster #2005 (Terpene bisphenol resin) manufactured by Yasushi Oil Industries Co., Ltd. (2) Material and dimensions of test piece The contents of the test piece are shown in Table 1.

【table】

〔Test conditions〕

For tensile shear test produced by the above method,
and adhesive samples for peeling tests, respectively.
JIS K-6850 (pulling speed 50mm/min) and JIS
The test was conducted under the conditions of K-6854 (pulling speed 200 mm/min). [Test Results] 1 Component A: 4 types of chlorinated polypropylene with different chlorine contents, Component B: 2 types of ethylene/vinyl acetate copolymers with different vinyl acetate contents, and Component C: 4 types of tackifiers. Table 2 shows the results of a tensile shear test on adhesion test pieces of propylene/ethylene block copolymer and SUS340 prepared by mixing various individual combinations.

[Table] 2 4 types of chlorinated polypropylene with different chlorine contents are used for the A component, and vinyl acetate content is used for the B component.
Adhesives with the compounding ratios shown in the table below, prepared by using 46% ethylene/vinyl acetate copolymer, rosin/glycerin ester and rosin modified phenol resin as component C, and each of component A and C alone. A peel test adhesive sample having layers was prepared using a polypropylene random copolymer sheet and a SUS430M plate, and the results of the peel test are shown in Table 3.

【table】

[Table] 3 The same materials as in 1 and 2 above were used for the adherend, the A component was chlorinated polypropylene with a chlorine content of 29.5% by weight, and the B component was ethylene/vinyl acetate copolymer with a vinyl acetate content of 46% by weight. Using the combination, both rosin glycerin ester and rosin modified phenol resin were used alone as component C, and adhesive samples having adhesive layers with various blending ratio compositions of A, B, and C were prepared, and for these, Table 4 shows the results of the tensile shear test and 180 degree peel test.

【table】

[Table] 4 For various adherends, adhesive samples were prepared using the same components A, B, and C as in 3 above, and tensile shear tests were conducted. Table 5 shows the results.

【table】

[Table] *Glass damage

Claims (1)

[Scope of Claims] 1. A polyolefin resin molded product and a polar different material, which are bonded via an adhesive layer having a composition consisting of at least the following components A and B, or a combination of A, B, and C. Composite products with materials. A: Chlorinated polypropylene with a chlorine content of 10 to 45% by weight B: Ethylene/vinyl acetate copolymer with a vinyl acetate group of 30 to 50% by weight. C: One type or a mixture of two or more types selected from the group of tackifiers consisting of modified rosin and phenolic resin. 2. The polyolefin resin molded product according to claim 1, wherein the composition of the adhesive layer is: A is 1 to 70% by weight of the total amount, and B/(B+C) is 20 to 100%. A composite product. 3. A composite product of a polyolefin resin molded product and a polar dissimilar material according to claim 1 or claim 2, wherein C is either rosin/glycerin ester or rosin-modified phenolic resin.