JPH0323582B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention has the processability and flexibility of a thermoplastic elastomer, but can be applied to polyolefins, polyamides,
Various resins such as polyester, as well as various rubbers,
It relates to adhesives with excellent heat resistance that can be used to bond a wide range of objects, including metals, glass, synthetic fibers, nonwoven fabrics, inorganic materials, and wood. [Prior art] In recent years, the compositeization of various industrial materials, mainly laminate films and composite materials, has become popular, and adhesive polymers used as adhesives have become more difficult to adhere to as composite materials become more highly functional. Synthetic resins with polar groups, synthetic resins without polar groups, metal materials such as iron, aluminum, copper, cellulose materials such as wood and paper, and composites of different materials such as glass are essential. It is widely used as an ingredient. It can be said that the high functionality of these composite materials is achieved by increasing the functionality of the adhesive polymer used for the adherend material. By the way, fields in which adhesive polymers are used as adhesives include furniture, building materials, plywood, woodworking, architecture, bookbinding, bag manufacturing, can manufacturing, packaging, etc., as well as vehicle-related fields, mainly automobiles, and electrical equipment. Including,
The scope of its use is extremely wide ranging from office equipment to household goods. Therefore, as mentioned above, there are many types of adherends, and their uses are also very diverse, so adhesive polymers are required to have various performances that suit the purpose. It is. Among these, polyolefin-based adhesive polymers, that is, those in which special functional groups are introduced into the polymer by modifying polyolefin-based resins such as polypropylene, polyethylene, and ethylene/α-olefin copolymers; Products synthesized using polar monomers as copolymerization components in the step process retain the physical properties and processability of polyolefin resins, while adding adhesion to various substrates, and can be used for extrusion coating and coextrusion. Various processing methods are used, including film, film lamination, coextrusion blow molding, and powder coating. [Problems to be solved by the invention] However, although the adhesive polymers obtained by these conventional techniques have a certain degree of adhesive performance, their durable adhesive performance under the usage environment is still insufficient, especially their heat resistance. Currently, products that can satisfy these requirements depend on a special polymer structure.
Most adhesives with excellent heat resistance require the use of resins with heat resistance, and to date no flexible thermoplastic elastomer adhesive polymer with excellent heat resistance has been obtained. [Means for Solving the Problem] The present invention has been made to solve the problems of the prior art described above, and in particular, it is a method for bonding a modified hydrogenated block copolymer graft-modified with an epoxy group-containing unsaturated compound. It was discovered that when used as a flexible polymer, it is useful as a soft to hard structural adhesive, and as an adhesive for composite materials with excellent heat resistance and high functionality. That is, the present invention provides a block copolymer comprising (1) a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer block B mainly composed of at least one conjugated diene compound. hydrogenated,
0.01 to 20 parts by weight of an epoxy group-containing unsaturated compound is added to 100 parts by weight of a hydrogenated block copolymer obtained by hydrogenating at least 80% of the aliphatic double bonds based on the conjugated diene compound in the copolymer. The present invention provides an adhesive obtained by grafting. The present invention will be described in detail below. The hydrogenated block copolymer which is the base of the adhesive used in the present invention is composed of a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer mainly composed of at least one conjugated diene compound. It is obtained by hydrogenating a block copolymer consisting of block B, for example, A-B.
-A, B-A-B-A, (A-B) ₄ -Si, A-B
It is a hydrogenated vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as -A-B-A. In addition, the hydrogenated block copolymer may contain 50% by weight of an A-B type hydrogenated block copolymer in addition to the one having the above-mentioned structure, if necessary.
It does not matter if it contains less than This hydrogenated block copolymer contains a vinyl aromatic compound in an amount of 5 to 95% by weight, preferably 10 to 85% by weight. The block structure is such that a polymer block A mainly composed of a vinyl aromatic compound is a homopolymer block of a vinyl aromatic compound or a vinyl aromatic compound containing more than 50% by weight, preferably 70% by weight or more of a vinyl aromatic compound. It has a structure of a copolymer block of a hydrogenated conjugated diene compound and a hydrogenated conjugated diene compound. It has the structure of a homopolymer block or a copolymer block of a hydrogenated conjugated diene compound containing more than 50% by weight, preferably 70% by weight or more, and a vinyl aromatic compound. be. In addition, a polymer block A mainly composed of these vinyl aromatic compounds, a polymer block B mainly composed of a hydrogenated conjugated diene compound, and a hydrogenated conjugated diene compound in the molecular chain of each polymer block. Alternatively, the distribution of the vinyl aromatic compound may be random, tapered (monomer component increases or decreases along the molecular chain), partially block-like, or any combination thereof, and the vinyl aromatic compound When there are two or more polymer blocks mainly consisting of a compound and two or more polymer blocks mainly consisting of the hydrogenated conjugated diene compound, each polymer block may have the same structure, or may have a different structure. It may be. As the vinyl aromatic compound constituting the hydrogenated block copolymer, one or more types can be selected from, for example, styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc.
Among them, styrene is preferred. Further, as the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound, for example, one type from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc. Or two or more kinds are selected, and among them, butadiene, isoprene and a combination thereof are preferred. and,
The microstructure of a polymer block mainly composed of a conjugated diene compound before hydrogenation can be arbitrarily selected; for example, in a polybutadiene block, the 1,2-vinyl bond structure accounts for 20 to 50%, Preferably it is 25-45%. Further, the number average molecular weight of the hydrogenated block copolymer used in the present invention having the above structure is 5000 to 5000.
1000000, preferably 10000 to 800000, more preferably 30000 to 500000, and the molecular weight distribution [weight average molecular weight (Mw) and number average molecular weight (Mn)]
(Mw/Mn)] is 10 or less. Further, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof. These block copolymers may be produced by any method as long as they have the above structure. For example, by the method described in Japanese Patent Publication No. 40-23798, a vinyl aromatic compound-conjugated diene compound block copolymer is synthesized in an inert solvent using a lithium catalyst. As a method for producing hydrogenated products of conjugated diene compound block copolymers, for example,
Although it can be obtained by the method described in Japanese Patent Publication No. 43-8704 and Japanese Patent Publication No. 43-6636, titanium-based water exhibits particularly excellent weather resistance and heat deterioration resistance of the hydrogenated block copolymer obtained. Hydrogenated block copolymers synthesized using added catalysts are most preferred; for example, JP-A-59-133203, JP-A-60-79005
The hydrogenated block copolymer used in the present invention can be synthesized by hydrogenation in the presence of a titanium-based hydrogenation catalyst in an inert solvent by the method described in the publication. At this time, at least 80% of the aliphatic double bonds based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer are hydrogenated, and the polymer block mainly composed of the conjugated diene compound is transformed into an olefin. It is necessary to convert the compound into a polymer block. In addition, hydrogen of an aromatic double bond based on a vinyl aromatic compound copolymerized into a polymer block A mainly composed of a vinyl aromatic compound and, if necessary, a polymer block B mainly composed of a conjugated diene compound. Although there is no particular restriction on the addition rate, it is preferable that the hydrogenation rate is 20% or less. The amount of non-hydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily determined using an infrared spectrophotometer, nuclear magnetic resonance apparatus, or the like. Next, as the epoxy group-containing unsaturated compound provided in the present invention, all compounds having an unsaturated group and an epoxy group in the molecule can be used, but as a preferable epoxy group-containing unsaturated compound, the following general formula is used. Examples include compounds represented by () and (). (In the formula, R represents hydrogen, a lower alkyl group, or a lower alkyl group substituted with a glycidyl ester group.) (In the formula, R represents hydrogen, a lower alkyl group, or a lower alkyl group substituted with a glycidyl ester group.) Preferred specific examples include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and allylglycidyl. Among them, preferred epoxy group-containing unsaturated compounds include glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether. In addition to these epoxy group-containing unsaturated compounds,
diglycidyl maleate, methylglycidyl maleate, ethylglycidyl maleate, isopropylglycidyl maleate, t-butylglycidyl maleate, diglycidyl fumarate, methylglycidyl fumarate, isopropylglycidyl fumarate, Epoxy group-containing unsaturated compounds such as diglycidyl itaconate, methylglycidyl itaconate, isopropylglycidyl itaconate, diglycidyl 2-methyleneglutarate, and methylglycidyl 2-methyleneglutarate can also be suitably used. These epoxy group-containing unsaturated compounds can be used alone or in combination of two or more. In order to obtain the modified hydrogenated block copolymer for the structural adhesive of the present invention, the epoxy group-containing unsaturated compound used during graft modification is usually in the range of 0.02 to 30 parts by weight per 100 parts by weight of the hydrogenated block copolymer. It can be suitably used. The modified hydrogenated block copolymer which is the structural adhesive of the present invention is produced by adding the above-mentioned epoxy group-containing unsaturated compound to the hydrogenated block copolymer having the above-mentioned structure in the presence or absence of an organic peroxide. The reaction can be carried out in either a molten state or a solution state. Furthermore, the modified hydrogenated block copolymer obtained by this modification reaction is 0.01 to 20 parts by weight, preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight per 100 parts by weight of the hydrogenated block copolymer. is grafted with an epoxy group-containing unsaturated compound,
The ratio of the molecular weight distribution of the modified hydrogenated block copolymer/the molecular weight distribution of the hydrogenated block copolymer at the time of final modification is
1.1-5.0, preferably 1.2-4.0, more preferably
It is between 1.2 and 3.0. If the amount of grafting exceeds 20 parts by weight, the effect of increasing the amount of grafting will not be noticeable, and the processability of the modified hydrogenated block copolymer will deteriorate, and undesirable components such as gel will be generated, making it undesirable as an adhesive. . Furthermore, if the amount of grafting is less than 0.01 part by weight, the adhesive performance will be poor, which is not preferable. If the ratio of the molecular weight distribution of the modified hydrogenated block copolymer and the unmodified hydrogenated block copolymer exceeds 5.0, undesirable components such as gel or low molecular weight components will be generated and the adhesive strength will be reduced. Moreover, if this ratio is less than 1.1, effective modification cannot be expected in terms of adhesive performance, which is not preferable. In addition, examples of organic peroxides that can be used as needed in the graft reaction of this modified hydrogenated block copolymer include dicumyl peroxide, di-tert-butyl peroxide, and tert-butyl peroxide.
-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butyl-peroxyhexine-3, n -Butyl-
4,4-bis(tert-butylperoxy)valerate, 1,1-bis(tert-butylperoxy)
Examples include 3,3,5-trimethylcyclohexane, and one or more types can be suitably selected from these. In addition to these organic peroxides, radical initiators such as 2,3-dimethyl-2,3, diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 2,3-dimethyl-2,3-diphenylbutane, (p-
methylphenyl)butane, 2,3-dimethyl-
The graft reaction may be carried out using a compound such as 2,3-di(bromophenyl)butane. The above-mentioned organic peroxides and radical initiators that can be used in this graft reaction can be suitably used in the range of usually 0.01 to 5 parts by weight per 100 parts by weight of the hydrogenated block copolymer. The method for producing the modified hydrogenated block copolymer, which is the adhesive of the present invention, is not particularly limited in the present invention, but the modified hydrogenated block copolymer obtained may deviate from the above-mentioned characteristics, or may become a gel. Production methods that include undesirable parts such as or that significantly increase the melt viscosity and deteriorate processability are not preferred. As an example of a preferred production method, for example, the hydrogenated block copolymer described above, an epoxy group-containing unsaturated compound, an organic peroxide, etc. are melt-kneaded at a temperature of 150 to 350°C in a vented extruder, and radical modification is performed. There is a way to do it. At this time, a stabilizer may be added as necessary to prevent the formation of gel or the like. Examples of the stabilizer include known antioxidants, and phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants can be used alone or in combination. At this time, polyolefin resin (olefin elastomer) and polystyrene resin (styrene elastomer) may be used together. The amount of the grafted epoxy group-containing unsaturated compound in the modified hydrogenated block copolymer can be easily determined by known methods, specifically, instrumental analysis such as infrared spectrophotometer, NMR, etc. The epoxy value can be determined by titration analysis, etc. The modified hydrogenated block copolymer of the adhesive obtained in the present invention has excellent adhesion performance alone, but it can also be used with other thermoplastic elastomers (polyolefin-based, polystyrene-based, nylon-based, polyester-based),
It is also part of the embodiments of the present invention to use thermoplastic resins (polyolefin, polystyrene, nylon, polyester) and known structural adhesives by methods such as melt mixing or in a dry blend state. Examples of adherends on which the modified hydrogenated block copolymer, which is the adhesive polymer of the present invention, exhibits good adhesive performance include metals, inorganic materials, glass, wood, nonwoven fabrics, leather, paper, polar resins, and non-polar resins. and known structural adhesives. The modified hydrogenated block copolymer of the present invention thus obtained can be used as an adhesive, particularly as a structural adhesive, in the form of a powder, pellet, sheet, or film using the above-mentioned adherend, for example, 2 Co-extrusion methods that use layered bottle molding machines, three-layer inflation molding machines, etc., extrusion coating methods that cover preheated materials to be coated by extrusion molding, T-die film (sheet) molding machines, and inflation molding. Adhesive layers can be coated using various known methods, such as the adhesive film (sheet) method in which a film (sheet) formed using a machine is bonded under heat, or the method in which powder coating is applied to the metal surface using an electrostatic coating machine or a fluidized coating machine. can be formed. [Effects of the Invention] The adhesive obtained by the present invention is particularly useful as a structural adhesive, and is based on a hydrogenated block copolymer having excellent heat resistance, weather resistance, and mechanical properties. Because it has an epoxy group introduced as a base, it can provide a high level of adhesion to various adherend materials through a heating reaction, and can be used for various metals, inorganic materials, paper, wood, other thermoplastic elastomers, and thermoplastics. Provides structural adhesives with excellent adhesive strength, heat resistance, and weather resistance to firmly adhere to adherends such as resins while melted. As specific application examples, it can be used as a laminate adhesive, an adhesive for laminate materials, an adhesive for making cans of chrome-plated steel sheets, and the like. [Example] Examples are shown below, but they are intended to explain the present invention more specifically, and are not intended to limit the present invention. Reference Example 1 Hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene structure, bound styrene content 35%, number average molecular weight 47000, molecular weight distribution 1.03, 1,2- Vinyl bond amount is 36%, hydrogenation rate is 99
% hydrogenated block copolymer (1), 1.5 parts by weight of glycidyl methacrylate, and 2.0 parts by weight of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed in a Henschel mixer. ,
Forced venting using a vacuum pump in a 45 mm diameter vented twin-screw extruder set at 190°C (degree of vacuum: 750
The denaturation reaction was carried out under pressure (mmHg gauge pressure). The obtained modified hydrogenated block copolymer (A), which is the adhesive polymer of the present invention, was refluxed with acetone in a Soxhlet extractor for 20 hours, and the epoxy value was titrated and analyzed, and 0.53 parts by weight of glycidyl methacrylate was grafted. It turned out that it was. Further, when the ratio of the molecular weight distributions of (A) and (1) was measured by GPC, it was 1.4. Reference example 2 has a structure of polystyrene-hydrogenated polybutadiene-polystyrene, and the amount of bound styrene is 28
%, number average molecular weight 63000, molecular weight distribution 1.04, 1,2-vinyl bond amount in the polybutadiene part before hydrogenation.
Hydrogenated block copolymer (2) 100 with a hydrogenation rate of 44% and a hydrogenation rate of 99%
parts by weight, glycidyl methacrylate 5.0 parts by weight,
0.6 parts by weight of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was mixed in a Henschel mixer, and the mixture was mixed using a vacuum pump in a vented twin-screw extruder with a diameter of 45 mm set at 230°C. The modification reaction was carried out while performing forced venting (degree of vacuum: 750 mmHg gauge pressure). The obtained modified hydrogenated block copolymer (B), which is the adhesive polymer of the present invention, was refluxed using acetone in a Soxhlet extractor for 20 hours, and titration analysis of the epoxy value revealed that 2.8 parts by weight of glycidyl methacrylate was grafted. It turned out that it was. Furthermore, when the ratio of the molecular weight distributions of (B) and (2) was measured by GPC, it was 2.7. Reference Example 3 Hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene structure, bound styrene content 60%, number average molecular weight 59000, molecular weight distribution 1.03, 1,2- Vinyl bond amount is 45%, hydrogenation rate is 99
% hydrogenated block copolymer (3), 2.5 parts by weight of glycidyl methacrylate, and 0.3 parts by weight of di-tert-butyl peroxide were mixed in a Henschel mixer, and the mixture was heated to 200°C in a 45 mm diameter vented The modification reaction was carried out in a axial extruder while performing forced venting (degree of vacuum: 750 mmHg gauge pressure) using a vacuum pump. The obtained modified hydrogenated block copolymer (C), which is the adhesive polymer of the present invention, was refluxed with acetone in a Soxhlet extractor for 20 hours, and the epoxy value was titrated and analyzed, and 1.44 parts by weight of glycidyl methacrylate was grafted. It turned out that it was. Furthermore, when the ratio of the molecular weight distributions of (C) and (3) was measured by GPC, it was 2.0. Reference example 4 has a structure of polystyrene-hydrogenated polybutadiene-polystyrene, and the amount of bound styrene is 30
%, number average molecular weight 73000, molecular weight distribution 1.04, 1,2-vinyl bond amount in the polybutadiene part before hydrogenation.
44% hydrogenated block copolymer with a hydrogenation rate of 99%, 70% by weight, has a polystyrene-hydrogenated polybutadiene structure, bound styrene content 30%, number average molecular weight 41000, molecular weight distribution 1.03, hydrogenated. 100 parts by weight of hydrogenated block copolymer (4) containing 30% by weight of a hydrogenated block copolymer with a 1,2-vinyl bond content of the previous polybutadiene part of 44% and a hydrogenation rate of 99%, glycidyl methacrylate 10.0 parts by weight and 0.6 parts by weight of di-tert-butyl peroxide were mixed in a Henschel mixer, and forced venting using a vacuum pump in a 45 mm diameter vented twin screw extruder set at 200°C (degree of vacuum: 750 mmHg gauge pressure). ) while carrying out the denaturation reaction. The obtained modified hydrogenated block copolymer (D), which is the adhesive polymer of the present invention, was refluxed for 20 hours using a Soxhlet extractor using acetone, and titration analysis of the epoxy value revealed that 6.7 parts by weight of glycidyl methacrylate was grafted. It turned out that it was. Furthermore, when the ratio of the molecular weight distributions of (D) and (4) was measured by GPC, it was 2.2. Example 1 A three-layer blow container (450ml cylindrical, Blow ratio 2.5) temperature
Formed at 180-230°C. When the obtained molded product was cut out and its adhesive performance was measured for T-peel adhesive strength (tensile speed: 50 mm/min) at 23°C, it was 3.6.
(Kg/25mm). Examples 2 to 8, Comparative Examples 1 to 6 Laminates were made under predetermined conditions using the various adherends and adhesive polymers shown in Table 1, and their adhesive performance was measured. The results are listed in Table 1. From these results, the adhesive made of the modified hydrogenated block copolymer of the present invention has extremely excellent adhesive strength.
Interlayer failure was observed in some adherends. On the other hand, it has been found that when an unmodified hydrogenated block copolymer is used as an adhesive, the adhesive strength is low and it is not suitable for practical use as an adhesive. Examples 9 to 12 The polymers synthesized in Reference Examples 1 to 4 were used as adhesive polymers, and the adherends had thicknesses of 0.3 mm and 2 mm.
Aluminum (0.3
A laminate of 2 mm)/adhesive polymer/aluminum (2 mm) was molded under bonding conditions of 200° C., 20 Kg/cm ² pressure, and 10 minutes. Note that the thickness of the adhesive polymer was 100 μm. A heat-resistant adhesion test was conducted using this laminate at a measurement temperature of 60°C. The results are listed in Table 2. These results revealed that the adhesive polymer of the present invention has heat-resistant adhesive performance as a structural adhesive.

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Claims (1)

[Claims] 1 Hydrogenating a block copolymer consisting of a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer block B mainly composed of at least one conjugated diene compound, A hydrogenated block copolymer obtained by grafting 0.01 to 20 parts by weight of an epoxy group-containing unsaturated compound to 100 parts by weight of a hydrogenated block copolymer obtained by hydrogenating at least 80% of the aliphatic double bonds based on the conjugated diene compound in the copolymer. adhesive.