JPS634875B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to high performance hot melt adhesives suitable for bonding plastics, rubber, metals, fibers, wood, leather, glass and the like. Hot melt adhesives made from synthetic resin materials are already used in many industrial fields, but the performance requirements for each application vary, and efforts are being made to design quality and improve performance in accordance with each requirement. . However, there are currently no satisfactory hot melt adhesives that can effectively bond different types of plastic materials with different polarities.
For example, when bonding a polyester base material and a polyamide base material, conventionally known polyester adhesives and polyamide adhesives are not suitable, and their adhesive strength with the same type of base material is high and practical. However, there is a problem in that adhesiveness with different types of substrates is poor. On the other hand, in the clothing field, adhesive interlining, adhesive sewing,
Ethylene copolymers (e.g. ethylene/ethyl acrylate copolymer, ethylene/vinyl acetate copolymer and partially saponified products thereof), copolyamides, copolyesters, etc. for use as non-woven fabric binders and joining patches. has been commercialized as a hot melt adhesive, but the amorphization caused by copolymerization tends to cause blocking of the powder, and the degree of this blocking is an important factor that determines the stability of the dotting process on the base fabric. . In addition, polyamides are known to be suitable hot melt adhesives in the field of making metal containers such as food cans and oil cans, and high-grade polyamides that maintain appropriate crystallinity have excellent adhesion and melting properties. It has been put into practical use because the temperature change in viscosity is relatively sharp, but it is easily affected by moisture, and the internal stress strain of the bonded part due to the relatively high glass transition point of the polyamide material. This has the disadvantage that the adhesive strength often decreases. The present inventors have conducted extensive studies with the aim of developing a hot melt adhesive for plastics, particularly a hot melt adhesive suitable for bonding between substrates with different polarities and surface characteristics, such as polyester base materials and polyamide base materials. , polyesteramides consisting of specific aliphatic components are extremely effective in adhering different types of plastic substrates, and at the same time, they can be used to bond metals, rubber,
We have discovered that it exhibits excellent performance as an adhesive for fibers, glass, etc., and have arrived at the present invention. That is, the present invention provides (A) at least one ester unit consisting of an aliphatic diol having 2 to 6 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms.
80% by weight and (B) amide units selected from aliphatic amino acids having 11 or 12 carbon atoms, lactams and aliphatic diamines having 4 to 12 carbon atoms and aliphatic dicarboxylic acids having 6 to 12 carbon atoms; The present invention provides a hot melt adhesive whose main component is a polyesteramide obtained by copolymerizing 95 to 20% by weight of at least one type of polyesteramide. Regarding adhesives made of polyesteramide, it has already been reported that polyesteramide containing an aromatic component has excellent adhesion to various materials (for example, in Japanese Patent Application Laid-Open No. 1989-1999).
Publication No. 22732, Japanese Patent Application Laid-open No. 1983-93781, Japanese Patent Application Publication No. 1983
-103265, U.S. Patent No. 4254254, etc.). In contrast to these prior examples, the adhesive made of aliphatic polyesteramide of the present invention has the following characteristics and has extremely high practical value. (1) Since the constituent components of the material are aliphatic components, an adhesive with a low glass transition point and high peel strength, especially at low temperatures, can be obtained. Further, it is expected that the adhesive strength will be improved by reducing the internal stress strain of the adhesive part, and furthermore, it is possible to design the quality of the adhesive as an extremely low melting point adhesive. (2) The aliphatic polyesteramide having the composition of the present invention is characterized in that its crystallinity decreases little due to copolymerization, and furthermore, its crystallinity does not greatly depend on the copolymerization composition. Therefore, it is particularly effective in reducing blocking, which is a problem in the process of powder adhesives for clothing, and also satisfies the property that the melt viscosity changes sharply around the melting point, which is required for metal adhesives. A useful adhesive can be obtained. The polyesteramide used as a material for the hot melt adhesive of the present invention is a copolymer obtained by copolymerizing an aliphatic polyester-forming component and an aliphatic polyamide-forming component. The ester unit, which is one component of this polyester amide, is mainly composed of an aliphatic diol having 2 to 6 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms. Representative examples of the components are listed below. and ethylene glycol, 1,3-propanediol, 1,
4-butanediol, 1,6-hexanediol, neopentyl glycol and adipic acid,
These include pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, and ester derivatives thereof. Each of these ester components can be used alone or in the form of a copolymer, and within a small amount of copolymerization, other polyester-forming components can be used, such as diols such as cyclohexanedimethanol, terephthalic acid, isophthalic acid, and phthalic acid. , dicarboxylic acids such as naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, and dimer acid, ε-caprolactone, polycaprolactone, and the like may be used. The amide unit, which is another component of the polyesteramide in the present invention, mainly includes aliphatic amino acids having 11 or 12 carbon atoms, lactams, aliphatic diamines having 4 to 12 carbon atoms, and aliphatic diamines having 6 to 12 carbon atoms. It is composed of at least one kind selected from amide units consisting of dicarboxylic acids, and representative examples of the constituent components include 11-aminoundecanoic acid,
Substantial combinations of 12-aminododecanoic acid, ε-laurolactam and tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine with adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid Examples include equimolar salts. Each of these amide components can be used alone or in the form of a copolymer of two or more, and other polyamide-forming components such as ε-caprolactam, 6-aminocaproic acid, hexane, etc. can be used within a small amount of copolymerization. Methylenediamine terephthalate,
Hexamethylenediamine isophthalate, 2,
It is also possible to introduce 2,4-/2,4,4-trimethylhexamethylenediamine terephthalate and the like. The polyester amide used in the present invention can be produced by the method already proposed by the present inventors (Japanese Patent Application No. 56-90855, etc.). , a polyamide-forming component consisting of a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid are mixed together and melt-polymerized. To give an example of a suitable polymerization method, in the presence of an esterification catalyst, a mixture of dicarboxylic acid, diol and amino acid, lactam, or diamine and dicarboxylic acid in an amount of 1.05 to 2.0 times the mole of the dicarboxylic acid, in the presence of an esterification catalyst, is added. After heating reaction at normal pressure at 150 to 260℃ under an inert gas seal in the absence of water, the reaction is carried out in the presence of a polymerization catalyst at 10 mmHg or less, preferably 1 mmHg.
By heating to 240 to 300°C under the following reduced pressure conditions, a polyesteramide with a high degree of polymerization that is uniform and transparent when melted can be obtained. In addition, a polyester prepolymer with an average degree of polymerization of 2 to 80 is first prepared from both diols and dicarboxylic acid derivatives under normal pressure and 150 to 260°C esterification conditions, and this prepolymer is combined with amino acids, lactams, nylon salts, etc. A uniform polyesteramide with a high degree of polymerization can be similarly obtained by supplying it to a polymerization reactor and carrying out heating polycondensation at 200 to 270° C. under reduced pressure. Conversely, a polyester amide can also be obtained by preparing a polyamide prepolymer having an average degree of polymerization of 2 to 100 consisting of an amide component in advance and carrying out polycondensation of the ester component in the presence of this prepolymer. Furthermore, polycondensation of polyester and polyamide prepolymers is also possible. Polymers polymerized using this prepolymer have a longer average segment length of polyester units and polyamide units than polymers obtained by mixing all the monomers at once and reacting them, and as a result, the melting point of the polymer is several degrees Celsius. ~20℃
It gets expensive. Therefore, the optimum method for producing the polymer should be selected depending on the intended use. Titanium-based catalysts give good results in the production of polyesteramides. Particularly preferred are tetraalkyl titanates such as tetrabutyl titanate, tetrapropyl titanate, tetraethyl titanate, and tetramethyl titanate, and metal salts of titanium oxalate such as potassium titanium oxalate. Other catalysts include dibutyltin oxide,
Examples include tin compounds such as dibutyltin laurate, lead compounds such as lead acetate, zirconium compounds such as tetraalkoxyzircon, and hafnium compounds. The copolymerization composition ratio of the polyester amide of the present invention is such that the composition ratio of ester units to amide units is 5 to 50% by weight to 95 to 20% by weight, more preferably 7 to 70% by weight.
A range of 93 to 30% by weight is suitable. Adhesives made from polyesteramide with this copolymer composition are better able to handle different types of plastic materials with different polarities and surface properties, such as polyester base materials and polyamide base materials, compared to conventional adhesives. Extremely effective for adhesion. Of course, it also exhibits high adhesive strength when bonding the same type of plastic materials, and it also uses copolyamide and copolyester adhesives, which are already known as adhesives for fibers, metals, rubber, glass, etc. shows unexpectedly excellent adhesion and stable process compatibility. There is no particular restriction on the degree of polymerization of the polyesteramide of the present invention, but generally speaking, it is one whose relative viscosity is within the range of 1.2 to 3.0 under the measurement conditions of 0.5% concentration in orthochlorophenol at 25°C. It can be set arbitrarily, and in particular, those in the range of 1.25 to 2.5 can be suitably used. Although there is no limit to the melting point or softening point of polyesteramide, there naturally exists a suitable range depending on the required performance in the adhesive application. For example, when used for side seam adhesion of food can containers, it is necessary to withstand a heat sterilization process at 100 to 125°C, and a copolymer having a melting point in the range of 150 to 200°C is preferred. melting point
If the fusion temperature is too high (over 200°C), the bonding process will be difficult, and the adhesive strength will drop noticeably due to deterioration of the polymer itself and deterioration of the organic paint applied to the can-making material. In addition, when used as an adhesive for clothing, it is necessary to reduce heat damage to woven fiber materials and at the same time have heat resistance to withstand hot water washing, so copolymers with a melting point or softening point of 80 to 140 degrees Celsius are usually preferred. . Even if the melting point is 140°C or higher, it can be used by adding plasticizers, adhesives, adhesion aids, and thermoplastic resins with low melting points and good fluidity. When used as a hot melt adhesive for plastics, the melting point or softening point basically needs to be lower than the melting point of the adhered substrate, and it is important to select it appropriately depending on the purpose of use, form, etc. During polymerization or processing, the polyesteramide constituting the adhesive of the present invention contains commonly known antioxidants, thermal decomposition stabilizers, light stabilizers, hydrolysis resistance improvers,
Pigments, dyes, lubricants, fillers, crystal nucleating agents, other polymers (for example, polyolefins known as adhesives, copolyamides, copolyesters), etc. can be optionally blended. Polyesteramide is used in the form of powder, film, thread, solution, dispersion, etc. for hot melt bonding of plastics, metals, fibers, wood, etc. The preferred method for forming the film is a melt-casting method, in which pellets or powder are fed into an ordinary extruder and extruded into a film at a forming temperature about 20 to 100°C higher than the melting temperature. The film-like hot melt adhesive thus obtained is applied in the form of a tape or to a part of plastic, woven fabric, metal, etc. that requires adhesion, and then this adhesive layer is sandwiched in a molten state to bond the plastic,
After the woven fabric or metal is pressed together, the adhesive layer is cooled and solidified to join the base materials. In addition, when pulverizing, it is cooled with a refrigerant such as liquid nitrogen, and then pulverized with a pulverizer.
Sometimes, a lubricant such as magnesium stearate, calcium stearate, silicic anhydride, or talc is added to form an adhesive powder. This powder is coated using a dotting machine, a sukiyata machine, etc. to form an adhesive interlining, and a woven outer fabric is layered on it.The adhesive layer is heated and softened using a hot roller, hot press, ironing, etc. to bond it. Let's do it. Woven fabrics include synthetic fibers such as polyester, polyamide, and acrylic, natural fibers such as wool and cotton, and blends thereof, and can also be applied to joining badges, name marks, etc.
Bonding of plastics and metals using adhesive powder can be carried out in the same way, but the powdered adhesive is applied to the metal by means such as fluidized dipping or powder spraying, and then the bonding is performed as described above. It is also possible. In addition, the polyesteramide of the present invention can be extrusion coated directly on the surface of plastics, metals, etc. in a heated molten state, or it can be coated on a substrate in the form of a solution or suspension in a specific solvent, and then the solvent is removed. It is also possible to complete the adhesion. The present invention will be explained in further detail by giving examples below. The characteristics of the polymers and adhesives described in Examples and Comparative Examples were evaluated by the following method. (1) Relative viscosity: 0.5 g of polymer was dissolved in 100 ml of orthochlorophenol and measured at 25°C. (2) Glass transition point and melting point: Manufactured by Perkin-Elmer
10℃/min using DSC-1B differential calorimeter
The temperature measured at a heating rate of (3) Softening point: Measured according to the method of JIS K6810. Example 1 65.5 parts by weight of 12-aminododecanoic acid, 32.4 parts by weight of dodecanedioic acid and 22.8 parts by weight of 1,4-butanediol
Part by weight was placed in a reaction vessel together with 0.04 part by weight of tetrabutyl titanate, and after purging with nitrogen, the reaction was heated at 220°C for 3 hours with stirring, and a mixture of water, tetrahydrofuran, and 1,4-butanediol was distilled out of the system. I left. Next, the reaction mixture was transferred to a polymerization reaction vessel, and 0.06 parts by weight of tetrabutyl titanate and the antioxidant "Irganox" 1010 were added.
250℃, 0.1mmHg in 1 hour after adding 0.10 parts by weight
The following conditions were brought about, and the polymerization reaction was further continued at 270°C for 2 hours. The obtained polymer was discharged from the polymerization container into water in a gut shape and pelletized through a cutter. The polyester amide thus obtained has a weight ratio of polyamide (N-12) part and polyester (PBD) part of 60:40, a relative viscosity of 1.30, a glass transition point of -10°C, and a melting point of
It was 120℃. Example 2 Polyesteramides B to N shown in Table 1 were prepared in the same manner as in Example 1 by changing the copolymerization composition ratio.

【table】

[Table] Example 3 The polyesteramide pellets obtained in Example 1 were fed into an extruder with a diameter of 400 mm equipped with a film die, and after melting at 200°C, they were formed into a film with a thickness of 50 μm and a film with a width of 1 cm. I slit the tape.
This tape was sandwiched between sheets of polyethylene terephthalate and polyhexamethylene adipamide with a thickness of 200μ, at a temperature of 170°C and a pressure of 1 kg/kg.
Samples were prepared by heat-pressure bonding at cm ² for 10 seconds. The sample obtained here was subjected to a T-peel test at 23℃ and -10℃ according to the method of JIS K6854 using Tensilon manufactured by Toyo Baldwin Co., Ltd. to determine the adhesive strength, as shown below. It showed an extremely high value. 23℃: 2.8Kg/cm -10℃: 2.4Kg/cm Comparative Example 1 N-
A 12/PBT:60/40 copolymer was obtained. The relative viscosity of polyesteramide containing this aromatic component is
1.30, the glass transition point was 35°C, and the melting point was 122°C. The polyester amide obtained here was used in Example 3.
When we examined the adhesive strength using the same procedure as above, we found that the peel strength at 23°C was high, but
It showed an extremely low value at a low temperature of -10℃. 23℃: 2.7Kg/cm -10℃: 0.3Kg/cm Example 4 Using the polyesteramide sample ~ prepared in Example 2, the adhesive strength to various plastic substrates was evaluated in the same manner as in Example 3. As shown in Table 2, it exhibited excellent strength.

【table】

[Table] Example 5 The polyesteramide sample ~ prepared in Example 2 was subjected to the same operation as in Example 3 to determine the thickness.
After forming a film of 50μ and width of 1cm, samples were prepared by heating and press-bonding the film with scissors between various metal bases preheated to 230°C for 10 seconds at a pressure of 1Kg/cm.
The sample obtained here was peeled off in the same manner as in Example 3, and the adhesive strength (at 23°C) was evaluated. As shown in Table 3, it showed excellent strength.

[Table] Example 6 Polyesteramide samples J to N prepared in Example 2 were subjected to the same operation as in Example 3 to determine the thickness.
After making a film of 100μ and 1cm width, it was sandwiched between two polyester/cotton broad base fabrics and pressed at 300g/cm ² using a hot press heated to 150℃.
A sample was prepared by bonding under heat and pressure for 10 seconds. The sample obtained here was peeled in the same manner as in Example 3 and the adhesive strength (23°C) was evaluated, and as shown in Table 4, it showed excellent strength.

【table】

Claims (1)

[Claims] 1 (A) 5 to 80% by weight of at least one ester unit consisting of an aliphatic diol having 2 to 6 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms, and (B)
At least one amide unit selected from aliphatic amino acids having 11 or 12 carbon atoms, lactams, aliphatic diamines having 4 to 12 carbon atoms, and aliphatic dicarboxylic acids having 6 to 12 carbon atoms, 95 to 20% by weight A hot melt adhesive whose main component is polyesteramide copolymerized with %.