JPS623871B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a new adhesive composition, more specifically, a block copolymer consisting of a conjugated diolefin polymer block and a monovinyl-substituted aromatic compound polymer block as a component, and in particular a polyolefin resin material and a metal material. The present invention relates to an adhesive composition suitable for bonding. In general, polyolefin resins such as polyethylene and polypropylene are well known as the most difficult plastics to adhere to. Since polyolefin resins are insoluble or poorly soluble in general solvents, they cannot be bonded by wetting them with a solvent or by preparing their own solvent solution. In addition, since it is highly crystalline and has no polar groups at all, even if ordinary commercially available adhesives are used, it will not adhere at all, or even if it does, it will only show weak adhesive strength. When bonding polyolefin resins that are difficult to bond, conventional methods include surface treatment of the adherend, such as roughening the surface by sandblasting, or immersion in a solvent such as perchlorethylene or trichlorethylene at approximately 80°C. A method of roughening the surface by soaking it for a period of time to elute the amorphous portion and low molecular weight portion of the surface, and a method of roughening the surface by eluting the amorphous portion and low molecular weight portion of the surface, and a method of roughening the surface by immersing it for a period of time to elute the amorphous portion and low molecular weight portion of the surface. Measures such as oxidizing and making it polar have been taken. However, even with these methods, sufficient adhesive strength cannot be obtained, and the polyolefin resin has not yet been completely bonded. Further, the above method requires extremely complicated operations and has the disadvantage that it alters or deteriorates the surface of the adherend. The present inventors have conducted extensive research on a simple and effective adhesive for polyolefin resins that overcomes all of the drawbacks mentioned above, especially adhesives that firmly bond polyolefin resins and metals. We have discovered that the object can be achieved by creating an adhesive composition with a specific composition containing a block copolymer consisting of a combined block and a monovinyl-substituted aromatic compound polymer block, and based on this knowledge, we have made the present invention. I've reached it. That is, the present invention provides (a) the general formula A-B-A, (A-B)n, B-(A-B) _o , (A-B) _-o A, or (A-B) _n In the formula, B is a block consisting essentially of a conjugated diolefin polymer, A is a block consisting essentially of a monovinyl-substituted aromatic compound polymer, and n is 2 to 10.
m is an integer of 3 to 7, X is a polyfunctional residue having m bonds), and the monovinyl-substituted aromatic compound content is
10 to 70% by weight, 100 parts by weight of at least one block copolymer with a molecular weight of 5,000 to 500,000, (b) 10 to 100 parts by weight of ethylene-vinyl acetate copolymer, and (c) 10 to 100 parts by weight of ethylene resin. (d) 5 to 100 parts by weight of a phenolic resin, and (e) 30 to 200 parts by weight of an adhesive resin. The block copolymer used as component (a) of the present invention has the general formula A-B-A, (A-B) _o , B-(A
-B) _o , (A-B) _-o A, or (A-B) _n It can be obtained by living anionic polymerization using a metal-based initiator. Such block copolymers can be produced by sequentially polymerizing monomers block by block in the presence of the initiator, or by simultaneously charging two types of monomers with different copolymerization reactivity ratios. The living block copolymer can be obtained by a method of coupling a living block copolymer with the above-mentioned initiator, or the like.
The block copolymer represented by (A-B) _n X can be obtained by coupling the living block copolymer A-B with a polyfunctional coupling agent. In this case, it is possible to use, for example, tetrafunctional coupling agents such as tin tetrachloride and silicon tetrachloride. Conjugated diolefins include 1,3-butadiene, 1,3-pentadiene, isoprene, 2,3
-dimethylbutadiene, and mixtures of two or more of these can be used. Examples of monovinyl-substituted aromatic compounds include styrene, α-
Examples include methylstyrene, o- or p-vinyltoluene, ethylstyrene, vinylxylene, isopropylstyrene, ethylvinyltoluene, tertiary-butylstyrene, diethylstyrene, vinylnaphthalene, and mixtures of two or more of these may also be used. can. The preferred combination is 1.3
-butadiene and styrene and isoprene and styrene. The molecular weight of the block copolymer is 5000~
500,000, preferably in the range of 20,000 to 400,000. If it is less than 5000, the resulting adhesive composition will have poor cohesive strength and will not have sufficient adhesive strength.
If it exceeds 500,000, the adhesive composition will have a high viscosity and will be impractical. The monovinyl-substituted aromatic compound content in the block copolymer is 10 to 10% of the total polymer.
It can be selected within the range of 70% by weight, preferably from 10 to 55% by weight; outside this range, the resulting adhesive composition will have poor adhesive strength, which is not preferred. The ethylene-vinyl acetate copolymer used as component (b) of the present invention has a vinyl acetate content of 10 to 45
% by weight, preferably in the range 20-40% by weight,
Melt index (JIS K 6760) 2~400
(g/10 minutes), preferably in the range of 20 to 350 (g/10 minutes). Vinyl acetate content
If it is less than 10% by weight, the resulting adhesive composition will have poor adhesion to metals, and if it exceeds 45% by weight, it will have poor adhesion to polyolefin resins, which is not preferred. Melt index is 2 (g/10
If it is less than 400 (g/10 min), the adhesive strength of the resulting adhesive composition will be poor, and if it exceeds 400 (g/10 min), the high temperature properties will deteriorate, which is not preferred. Ethylene-
The vinyl acetate copolymer is used in an amount of 10 to 100 parts by weight based on 100 parts by weight of the block copolymer. Outside this range, the desired adhesive strength cannot be obtained, which is not preferable. The ethylene resin used as component (iii) of the present invention includes polyethylene, modified polyethylene (for example, one grafted with maleic acid, etc.), and ethylene and unsaturated carboxylic acid (for example, acrylic acid, etc.).
methacrylic acid, itaconic acid, etc.) or ethylene and unsaturated carboxylic acid esters (such as methyl acrylate, ethyl acrylate, etc.)
There are products in which a part of the hydrolyzed copolymer with monovalent or divalent metal (for example, sodium, magnesium, zinc, etc.) is neutralized. A preferred ethylene resin is polyethylene. Ethylene resin has a density (JIS K 6760) of 0.910 to 0.980.
g/ ^cm3 , and is in the range of melt index (JIS
K 6760) can be selected in the range of 0.01 to 50 (g/10 minutes). Melt index is 0.01
If it is less than (g/10 minutes), the resulting adhesive composition will have poor adhesive strength, and if it exceeds 50 (g/10 minutes), its high temperature properties will deteriorate, which is not preferable. Polyethylene is used in an amount of 10 to 100 parts by weight of the block copolymer.
Used in the range of 100 parts by weight. Outside this range,
This is not preferable because the desired adhesive force cannot be obtained. The phenolic resin used as component (2) of the present invention is a reaction product of phenol or alkylphenol and formaldehyde, and is not limited as long as it is thermoplastic and non-thermally reactive. , those modified with natural resins (eg, rosin, etc.) may also be used. Specific examples of the phenolic resin include condensates of formaldehyde and phenol, p-tertiary octylphenol, p-tertiary amylphenol, p-tertiary butylphenol, and the like. The phenolic resin is used in an amount of 5 to 100 parts by weight based on 100 parts by weight of the block copolymer. If it is less than 5 parts by weight, the resulting adhesive composition will have poor adhesive strength, and if it exceeds 100 parts by weight, the resulting adhesive composition will be brittle and is not preferred as an adhesive. The adhesive resin used as the component (e) of the present invention is particularly limited to one or more of rosin resins, terpene resins, hydrogenated hydrocarbon resins, styrene-olefin copolymer resins, etc. It's not a thing. Specific examples of rosin-based resins include rosin,
Examples include hydrogenated rosin, disproportionated rosin, glycerin esters thereof, and pentaerythritol esters. Specific examples of the terpene resin include α-pinene polymer, β-pinene polymer, dipentene polymer, α-pinene-phenol copolymer, and β-pinene-phenol copolymer. Specific examples of hydrogenated hydrocarbon resins include:
Products obtained by polymerizing and hydrogenating the C ₄ and C ₅ fractions in cracked naphtha oil as raw materials, products obtained by polymerizing and hydrogenating the C ₉ fraction in cracked naphtha oil as raw materials, and cyclopentadiene in cracked naphtha oil Examples include those obtained by polymerizing and hydrogenating cracked oil whose main component is The adhesive resin is 30 parts by weight per 100 parts by weight of the block copolymer.
Used in the range of ~200 parts by weight. If it is less than 30 parts by weight, the desired adhesive strength cannot be obtained, and if it exceeds 200 parts by weight, the resulting adhesive composition itself becomes highly tacky, which is unfavorable for work. If desired, auxiliary substances commonly used in adhesives, such as antioxidants, may be added to the above composition. Since each block in a block copolymer undergoes a different deterioration mechanism, it may be more effective to combine various antioxidants.
Further, if necessary, common elastomers, plasticizers, pigments, fillers, etc. can be added. Various methods can be used to manufacture the adhesive composition of the present invention. For example, a melting kettle, kneader, mixing roll, extruder, internal mixer, etc. can be used. The adhesive composition of the present invention includes polyolefin resins (e.g., polyethylene, polypropylene, ethylene copolymers, etc.), polyolefin resins, metals (e.g., iron, aluminum, stainless steel,
It is useful for bonding to materials such as copper, brass, etc.), paper, wood, and plastics other than polyolefin resins. In particular, it shows extremely excellent adhesion to polyolefin resins and metals. Various methods can be used for adhesion. For example, a method using an extruder, a hot melt applicator, a hot melt coater, etc., and forming the adhesive composition into a film, pellet, or powder, and sandwiching it between adherends;
A method using heat and pressure can be used. Examples are shown below. The examples illustrate the invention but do not limit the scope of the invention. Examples 1 to 5 In a nitrogen gas atmosphere, n-butyllithium was added to an n-hexane solution containing a mixture of 1,3-butadiene and styrene, and after most of all monomers were copolymerized, 1. An n-hexane solution containing a mixture of 3-butadiene and styrene was added, and polymerization was carried out until almost all of the additional monomer was copolymerized. The obtained polymer is a polybutadiene-polystyrene-polybutadiene-polystyrene type block copolymer, with a molecular weight of 80,000,
The styrene content was 40% by weight. Based on 100 parts by weight of the obtained block copolymer, 32.5 parts by weight of ethylene-vinyl acetate copolymer (Sumitate KE-10 manufactured by Sumitomo Chemical, vinyl acetate content 28% by weight, melt index 300), polyethylene (download) Polyethylene L-1745 manufactured by Asahi Dow, density 0.917g/cm ³ , melt index 3)
25 parts by weight, 32.5 parts by weight of phenol resin (CKM-2400, manufactured by Showa Union Gosei), 65 parts by weight of α-pinene polymer (Picolite A-115, manufactured by Etsuso Chemical), and 1,1-bis-(4-hydrocarbonate). Sipheanil) -
1 part by weight of cyclohexane (Antigen W manufactured by Sumitomo Chemical) was charged into a pressure kneader and melt-kneaded at 120°C to obtain a composition. This composition was made into a 0.4 mm thick sheet using a hot press. As the adherend, a sanded 1.6 mm thick mild steel plate with a density of 0.947 g/cm ³ was used.
Polyethylene (molded into a 1 mm thick sheet) with a melt index of 0.15 was used. Adhesive sheet and mild steel plate are bonded at 160℃, then polyethylene sheets preheated to 200℃ are overlapped and crimped.
A laminate was made from mild steel plate/adhesive/polyethylene. The adhesive/polyethylene double layer was cut into 10 mm width samples to be used as peel test samples. The peel test was conducted at a peel rate of 50 mm/min. The result is the first
Shown in the table. In the above formulation, the results of varying the amounts of various ingredients are shown together with comparative examples. Also, as adhesive resins, terpene-phenol resin (YS Resin Px 600, manufactured by Yasushi Oil Co., Ltd.), rosin glycerin ester (Ester Gum H, manufactured by Arakawa Forestry Chemical Co., Ltd.) ) and the results using hydrogenated hydrocarbon resin (Alcon M90, manufactured by Arakawa Forestry Chemical Co., Ltd.) are shown in Table 1.

【table】

[Table] Examples 6 to 8 In a nitrogen gas atmosphere, n-butyllithium is added to a toluene solution containing styrene to initiate polymerization of styrene. After 99% or more of the styrene has been polymerized, 1,3-butadiene is added. 99 of the added 1,3-butadiene.
After % or more had polymerized, silicon tetrachloride was added to carry out a coupling reaction without losing activity. The obtained polymer is a (polystyrene-polybutadiene) ₄ Si type block copolymer,
It had a molecular weight of 170,000 and a styrene content of 30% by weight. Based on 100 parts by weight of the obtained block copolymer, 45 parts by weight of ethylene-vinyl acetate copolymer (Evaflex 150, manufactured by Nippon Polychemical, vinyl acetate content 33% by weight, melt index 25),
Polyethylene (Santec J-340 manufactured by Asahi Kasei, density 0.955, melt index 7) 35 parts by weight, phenolic resin (CKM 2400) 30 parts by weight, α
-Pinene polymer (YS Resin A800, manufactured by cheap crude oil)
After kneading 80 parts by weight and 1 part by weight of 1,1-bis-(4-hydroxyphenyl)-cyclohexane (antigen W) in the same manner as in Example 1, the same test was conducted. The results are shown in Table 2. In the above formulation, the results of varying the amounts of various ingredients are shown in Table 2 together with comparative examples.

[Table] As mentioned above, block copolymers consisting of a conjugated diolefin polymer block and a monovinyl-substituted aromatic compound polymer block, ethylene-vinyl acetate copolymers, ethylene resins, phenolic resins, and adhesive resins The adhesive composition of the present invention, which is composed of It also shows excellent adhesion to polyolefin resins and metals, making it suitable for practical use as an adhesive between polyolefin resins and metals.

Claims (1)

[Claims] 1 (a) General formula A-B-A, (A-B) n, B-(A-B) _o , (A-B)- _o A, or (A-B) _n X (B in the formula is substantially a blossom that consists of a conjunctive geolefin polymer, A is essentially a monovinyl substitutional compound polymer, and N is 2-10
m is an integer of 3 to 7, X is a polyfunctional residue having m bonds), and the monovinyl-substituted aromatic compound content is
10-70% by weight, 100 parts by weight of at least one type of block copolymer with a molecular weight of 5,000-500,000, (b) 10-100 parts by weight of ethylene-vinyl acetate copolymer, (c) 10-100 parts by weight of ethylene resin. (ii) 5 to 100 parts by weight of a phenolic resin, and (e) 30 to 200 parts by weight of an adhesive resin. 2. The adhesive composition according to claim 1, wherein A in the general formula is a block consisting of styrene or a polymer of alkyl-substituted styrene. 3 B in the general formula is 1,3-butadiene, 1,3
- The adhesive composition according to claim 1, which is a block consisting of a polymer of pentadiene, isoprene or 2,3-dimethylbutadiene.