JPS6157354B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive composition,
Specifically, the present invention relates to an adhesive composition with excellent heat resistance and water resistance, and particularly provides an adhesive composition suitable for bonding when at least one of the objects to be adhered is glass or ceramics. be. Conventionally, there has been no adhesive suitable for bonding when at least one of the objects to be bonded is glass or ceramics, and many problems remain in the industry that uses glass or ceramics. For example, when manufacturing molded products of glass or ceramic materials, it is ideal to melt and bond (fusion) mold the materials themselves without using adhesives in order to take advantage of the characteristics of these materials. The material has a very high softening point (e.g. Pyrex glass approximately 850℃, soda glass approximately 600℃).
~650℃ alumina 1700~1800℃) There were problems such as requiring a large amount of heat source, making it difficult to put it into practical use. It is possible to bond the same materials together, such as glass-to-glass and ceramics-to-ceramics, but when manufacturing molded products by combining materials of different materials, for example, in the case of glass-plastics, glass-metal, etc. , it is obvious that this is impossible because the adhesive strength does not increase. Furthermore, depending on the shape of the molded product, its purpose of use, and the conditions of use, processing using an adhesive can produce more precise products and is more economical. Various adhesives have been developed from these viewpoints. Inorganic adhesives can withstand high temperatures of 300℃ or higher and have excellent airtightness and water (humidity) resistance, but they have poor chemical resistance, require the atmosphere inside the heating furnace to be adjusted during baking, and are difficult to cure. It has disadvantages such as requiring high temperatures, which causes poor productivity and workability, so it is not used much. On the other hand, conventional organic adhesives have very good adhesive strength at room temperature, but have poor airtightness, heat resistance, and water (moisture) resistance, and especially when used for a long time at around 150°C, the adhesive strength decreases, resulting in long-term use. There are many deficiencies such as loss of transparency when exposed to water or sunlight for a long time, and the material properties of adherends such as glass and ceramics cannot be fully demonstrated. The adhesive composition of the present invention combines the advantages of conventional inorganic adhesives and organic adhesives, such as heat resistance, water (moisture) resistance, airtightness, and weather resistance, and is effective in adhering glass and ceramics together. Of course, it exhibits extremely excellent adhesion performance with dissimilar materials (plastics, metals). Furthermore, by blending this adhesive with glass powder, fibers, ceramics, metal powder, etc., either singly or in a mixture, to create compression adhesive molded products, the filling properties will be increased, and additional benefits such as superior molded products can be produced. This led to the completion of the present invention. The novel adhesive composition of the present invention is A (R ₁ represents H or CH ₃ group, R ₂ represents H or alkyl group) (R ₃ represents H or CH ₃ group, R ₄ represents an alkylene residue) as a monomer unit at least 80% by weight, and has a hydroxyl value of 80 to 350 and an acid value of 0 to 250. , a copolymer resin having an average molecular weight of 500 to 10,000, B an amino resin and/or a polyfunctional isocyanate, and C an epoxy resin if necessary. Used for the above-mentioned A component constituting the adhesive composition of the present invention. As long as R ₁ represents H or a CH ₃ group, and R ₂ represents a H or an alkyl group, preferably a straight or branched alkyl group having 1 to 8 carbon atoms, there are no particular restrictions. For example, acrylic acid, methyl acrylate, ethyl acrylate,
Propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, methacrylic acid,
Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and arbitrary mixtures thereof. Also used for the above A component There are particular restrictions on compounds in which R ₃ represents H or CH ₃ group, and R ₄ represents an alkylene residue, preferably a linear or branched alkylene residue having 1 to 6 carbon atoms. hydroxymethyl esters, hydroxyethyl esters, hydroxypropyl esters, hydroxybutyl esters, hydroxypentyl esters and hydroxyhexyl esters of acrylic acid, hydroxymethyl esters and hydroxyhexyl esters of methacrylic acid, and any mixtures thereof, etc. It is. The A component of the present invention is and contains at least 80% by weight as a monomer unit, and has a hydroxyl value of 80 to 350 and an acid value of 0 to 250,
It is a copolymer with an average molecular weight of 500 to 10,000, but Other monomers to be copolymerized with are not particularly limited, but examples include styrene, α-methylstyrene, methacrylamide, N-methylolmethacrylamide, acrylamide, diallyl phthalate, allyl glycidyl ether, glycidyl methacrylate, and 2-ethylhexyl glycidyl. Examples include ether, vinyl acetate, acrylonitrile, and vinyl propionate. These monomers can be synthesized by any conventionally known polymerization method, such as bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization under normal pressure or under pressure, and the usual radical polymerization methods used in the field. However, solution polymerization and bulk polymerization are preferred from the standpoint of easily obtaining a product with a relatively small molecular weight. Number average molecular weight of copolymer (A) (vapor pressure osmosis method,
Vapor/Pressuve osmometry Method) is approximately 500
It is preferably 10,000 to 10,000, more preferably 700 to 5,000. When the number average molecular weight is 500 or more, the heat resistance and water (moisture) resistance are improved, and the airtightness and adhesive strength are also significantly improved.When the number average molecular weight is 10,000 or less, although the composition is hard, it is not brittle and exhibits high elasticity. Furthermore, within this molecular weight range, glass-to-glass, ceramic-to-ceramic, and glass-to-ceramic adhesion properties are extremely excellent. The composition ratio of each monomer constituting the component A is such that the hydroxyl value of the resulting copolymer component A is preferably 80 to 80.
350, more preferably in the range of 100 to 300, and the acid value is preferably in the range of 0 to 250, even more preferably 0 to 300.
Select to be within the range of 150. This is because within this range, the adhesive strength is even stronger and the adhesive strength is extremely excellent even with different types of materials. On the other hand, the amino resin, which is one of the B components constituting the adhesive composition of the present invention, is not particularly limited, and includes etherified methylolmelamine resin,
For example, methylated methylol melamine, ethylated methylol melamine, butylated methylol melamine, isopropylated methylol melamine, amylated methylol melamine and etherified methylol urea resins, such as methylated methylol urea and also etherified methylol urea melamine cocondensates. Any mixture of . These amino resins are preferably blended in an amount of 0.2 to 10 reaction equivalents per equivalent of hydroxyl group in the composition. This is because when the amount of amino resin blended is less than 0.2 reaction equivalent, stickiness becomes strong and various physical properties such as heat resistance, water (moisture) resistance, and chemical resistance decrease, while on the other hand, when the amount blended exceeds 1.0 reaction equivalent. , the adhesive layer is soft, has poor airtightness, and has poor adhesive strength. After the adhesive containing the amino resin is applied and the objects to be adhered are stacked and pressed together, it is cured at a temperature of 80 to 250°C, preferably 100 to 220°C, for 1 to 120 minutes, preferably 5 to 60 minutes. Further, as the polyfunctional isocyanate compound which is one of the B components of the present invention, tolylene diisocyanate and its hydrogenated product, adduct 4,4'-diphenylmethane diisocyanate, dianisidine diisocyanate, tridene diisocyanate,
Hexamethylene diisocyanate, metaxylylene diisocyanate, phenyl isocyanate,
Parachlorophenyl isocyanate, orthochlorophenyl isocyanate, methyl isocyanate, ethyl isocyanate, n-butyl isocyanate, n-propylisocyanate, octadecyl isocyanate, 1,5-naphthalene diisocyanate, polymethylene polyphenyl isocyanate, transpine diisocyanate, methylene bis- Di-phenyl isocyanate and its hydrogenated product, xylene diisocyanate and its hydrogenated product, triallylisocyanurate, dimethylsilane diisocyanate, diphenylsilane diisocyanate, cyclohexane-1,4-diisocyanate, 1,3-phenylene diisocyanate, functional Examples include blocked polyisocyanates in which groups are blocked, and arbitrary mixtures thereof. These polyfunctional isocyanates are preferably used in an amount of 0.7 to 1.5 per equivalent of hydroxyl group in the copolymer.
They are blended in proportions of reaction equivalents. This is because when the amount of polyfunctional isocyanate blended is less than 0.7 reaction equivalent, reactivity is poor, stickiness is poor, and heat resistance and
Various physical properties such as water (moisture) resistance and chemical resistance deteriorate.
On the other hand, when the blending amount exceeds 1.5 reaction equivalents, it has poor adhesive strength and low elasticity, and is inferior in properties such as airtightness and corrosion resistance. Adhesives containing polyfunctional isocyanates are
After the objects to be coated and adhered are stacked and pressed together, the adhesive is cured at a temperature of 0 to 150°C, preferably 10 to 100°C, for 0 to 50 hours, preferably 3 seconds to 8 hours. The copolymer resin as component A and the amino resin and/or polyfunctional isocyanate as component B may be mixed by a conventionally known method and there are no particular limitations. The epoxy resin that is optionally blended into the adhesive composition of the present invention is mainly blended according to the following needs. That is, the adhesive is less brittle, can withstand repeated rapid heating and cooling, and exhibits less deterioration in performance at low temperatures. Also, the adhesive strength with metals is increased. Further, the epoxy resin used in the adhesive composition of the present invention is not particularly limited, and may be any resin containing a highly reactive epoxy group in one molecule, such as glycidyl ether type epoxy resin,
Examples include glycidyl ester type epoxy resins, linear aliphatic epoxy resins, and alicyclic epoxy resins. The novel adhesive for glasses and ceramics of the present invention contains, in addition to the above-mentioned copolymers, epoxy resins, amino resins, and/or polyfunctional isocyanates, catalysts for accelerating the reaction, organic solvent dyes and pigments, and antiseptics. Additives such as oxidizing agents, ultraviolet absorbers, and stabilizers do not cause any problems. Further, the blending amounts of these additives are equivalent to conventionally known amounts. The bonding method of the present invention is a method in which a viscous liquid is uniformly applied onto an object to be adhered, and another object to be adhered is overlapped and pressure bonded, or a resin film is applied on the object to be adhered. There are no particular restrictions, and the method may be the same as the conventional method, such as making a sheet, overlapping another sheet to be adhered, and applying heat and pressure to bond. Next, the A component copolymer resins (copolymer resins No. 1 to 6) constituting the adhesive composition of the present invention and the copolymer resins (copolymer resin No. 7) that do not constitute the adhesive composition of the present invention will be described. The preparation method of ~9) will be described.

[Table] Place the reactor equipped with a dropping device, a stirrer, a reflux condenser, and a thermometer and raise the temperature to 110°C while stirring. After raising the temperature, continuously drop the monomer mixture shown in the table over about 5 hours. After the addition was completed, the reaction was continued for an additional 2 hours. The obtained resin liquid was concentrated in vacuo to reduce the volatile content to 1
% copolymer resin No.1 was obtained. Polymerization was carried out in the same manner, changing the monomer composition as shown in Table 1, to produce nine types of copolymer resins Nos. 2 to 9. Table 1 shows the properties of these copolymer resins.

【table】

[Table] The abbreviations for monomers in the monomer composition are as follows. AA...acrylic acid, MA...methyl acrylate, EA...ethyl acrylate, BA...butyl acrylate, EHA...2ethylhexyl acrylate, MMA...methyl methacrylate, BMA...butyl methacrylate, EHMA ...Methacrylic acid 2
Ethylhexyl, 2HEA...2-hydroxyethyl acrylate, 2HEMA...2-hydroxyethyl methacrylate, HPMA...hydroxypropyl methacrylate, AN...acrylonitrile. The adhesive composition of the present invention will be described in detail below using Examples and Comparative Examples. Examples 1 to 9, Comparative Examples 1 to 6 Each copolymer resin obtained in the reference example is shown in Table 2.
0.3 part of para-toluenesulfonic acid was added to the mixture shown in (Examples 1 to 9) (Comparative Examples 1 to 9).
6) Adhesive was prepared. The amino resins and epoxy resins used in Table 2 are as follows.

【table】

[Table] Nikaratsuk MW-30 (methylated methylolmelamine) manufactured by Sanwa Chemical Co., Ltd., Nikaratsuk MS-001
(Butylated methylolmelamine) Sanwa Chemical Co., Ltd.
Nikaratsuku MX-201 (methylated methylol urea) manufactured by Sanwa Chemical Co., Ltd., Epicote 1001 manufactured by Ciel Chemical Co., Ltd., Epicote 815 manufactured by Ciel Chemical Co., Ltd., and Epicote 1007 manufactured by Ciel Chemical Co., Ltd. Examples 10 to 14, Comparative Examples 7 to 9 The resin obtained in Reference Example 1 was prepared so that the polyfunctional isocyanate shown in Table 3 and -OH in the resin were OH/NCO = 1/1. mixture. Further, 0.10% by weight of an amine catalyst based on the resin content was added to prepare adhesives of Examples 10 to 14 (Comparative Examples 7 to 9). In addition, the amount of epoxy resin added is the weight% based on the total amount of resin and isocyanate resin used.
It was shown in The polyfunctional isocyanates used in Table 3 are as follows. Coronate L (TDI) manufactured by Nippon Polyurethane Co., Ltd.
Takenate D-120N (H ₆ × DI) Manufactured by Takeda Pharmaceutical Co., Ltd.

【table】

[Adhesion test]

Apply adhesive to two hard glass plates (thickness: 5 mm) that have been soaked in a chromic acid mixture to remove oils, fats, dust, etc., and if they contain solvent, air dry to volatilize the solvent. The adhesive surfaces of the two glass plates were joined together, and the adhesion was completed at 180° C. for 20 minutes under a load of 1 Kg/cm ² . The adhesives shown in Table 3 were cured for 2 days after adhesion under conditions of 50°C x 20 minutes. The adhesive strength after the cold/heat cycle test and the water resistance test was measured from the tensile shear strength. Γ measurement method: According to JIS K 6850. Γ measurement conditions: adhesive area 15mm x 3mm, measurement temperature 25℃
Adhesive thickness 0.05mm Γ Cold cycle test: 30℃ (10 minutes) 100℃ (10 minutes)
Measure those that do not peel off after 20 rapid cooling/heating cycles (minutes). Γ Water resistance test: Measured on items that did not peel off after being immersed at room temperature for 10 days. The results are shown in Table-4. Also, glass and metal plates,
Measuring the tensile shear strength when bonding different materials such as plastic plates with the adhesive of the present invention,
It is shown in Table-5.

【table】

[Adhesion airtightness test]

A pressure-resistant glass ampoule with a wall thickness of 4 mm, a diameter of 20 mm, and a length of 200 mm was cut from the center, the part was finished with a slit, and the slit was adhesively bonded under the conditions of Example 1. Approximately 5 g of completely dried blue silica gel was introduced and sealed while reducing the pressure to 2 mmHg using a vacuum line. Place this ampoule in a sunshine weather meter (repeatedly dispersing water for 15 minutes after 45 minutes in an atmosphere of 50°C).
The airtightness was determined based on the amount of water absorbed by the silica gel over time of 500 hours, 1000 hours, and 1500 hours. The results are shown in Table-6. Absorption rate (%) = Silica gel weight after test - Silica gel weight / Silica gel weight x 100

【table】

【table】

Claims (1)

[Scope of Claims] 1. An adhesive composition comprising: A (R ₁ represents H or CH ₃ group, R ₂ represents H or alkyl group) (R ₃ represents H or CH ₃ group, R ₄ represents an alkylene residue) as a monomer unit at least 80% by weight, and has a hydroxyl value of 80 to 350 and an acid value of 0 to 250. A curable adhesive composition comprising: a copolymer resin having an average molecular weight of 500 to 10,000, B: an amino resin and/or a polyfunctional isocyanate, and C: an epoxy resin if necessary. 2. The curable adhesive composition according to claim 1, wherein at least one of the objects to be adhered is glass or ceramics.