JPH0129515B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an ionizing radiation-curable hot melt adhesive. More specifically, the present invention relates to an ionizing radiation-curable hot melt adhesive for fibers that has excellent adhesive properties, solvent resistance, water resistance, and heat resistance. [Prior art] Hot melt adhesives have been used in the textile industry in recent years to shorten the sewing process, make the finish more uniform, and take advantage of the characteristics of hot melt adhesives, such as their fast adhesion speed and the ability to obtain strong adhesive force instantly after cooling. It is often used in adhesive interlining for the purpose of rationalization, etc. (``Actual Practice of Hot Melt Adhesion'', Kobunshi Publishing Co., Ltd., 1979). Conventionally, in this field, nylon adhesives with excellent dry cleaning resistance, polyester adhesives with excellent hot water washing resistance, and the like have been used. Recently, polyether ester adhesives have been developed (Japanese Patent Laid-Open No. 153835-1983). Furthermore, as a reactive adhesive,
Reactive hot melt adhesives containing epoxy groups, isocyanate groups or activated silyl groups have been developed. Conventionally, cloth has been bonded by thermocompression bonding using a hot melt adhesive as described above. Furthermore, very recently, an electron beam-curable resin has been developed that is made by introducing a double bond sensitive to electron beams into the terminal end of a polyester resin (Japanese Patent Laid-Open Publication No.
59-84919, JP-A-58-32617, JP-A-58-
32618). [Problems to be Solved by the Invention] Adhesives conventionally used for bonding cloth have the following problems. In other words, currently commercially available hot melt adhesives for textiles are heat resistant,
They do not necessarily satisfy water resistance, solvent resistance, etc. Nylon adhesives have excellent dry cleaning resistance but poor hot water washing resistance, and polyester adhesives have hot water resistance. It is currently becoming mainstream due to its excellent washability and good texture, but it has the problem of poor dry cleaning resistance. Further, these hot melt adhesives for textiles have problems in that repeated iron pressing causes deterioration in adhesive strength and oozing of the adhesive. In order to solve these problems, reactive adhesives have been developed, but these adhesives have satisfactory performance in terms of suitability as a textile adhesive, heat resistance, water resistance, and solvent resistance. has not been obtained. That is, instant adhesives such as α-cyanoacrylate and anaerobic adhesives such as dimethacrylate are well known as reactive adhesives, but these are liquid at room temperature, and when used for textiles, they are difficult to apply. Bleeding is observed, making it unsuitable for use in textiles. As a hot melt adhesive for textiles, it is desirable to use one that is solid at room temperature, but if you try to incorporate a double bond into a polyester or nylon adhesive resin and perform a three-dimensional reaction using a radical initiator, the adhesive will break down. The adhesive must be a two-component type, which is inconvenient for bonding work. In addition, reactive adhesives containing reactive isocyanate groups or active silyl groups have been developed, but these types of adhesives are extremely unstable against moisture in the air.
Lacks storage stability. Furthermore, adhesives having epoxy groups, which are reactive functional groups, have been developed, but when used, the adhesive must be of a two-component type, which causes inconvenience in the bonding work. As described above, in the field of bonding fiber materials using adhesives, many problems remain to be solved regarding the adhesives used. If a reactive hot melt adhesive is to be used for bonding fibers, the adhesive must satisfy the following conditions (i) to (iv). (i) Demonstrate adhesive strength that can be handled within a short time after bonding. (ii) It should not show thermal solubility when reheated after curing. (iii) It does not lose its flexibility even after curing and has excellent dry cleaning resistance and washing resistance. (iv) Have long-term storage stability. [Means for solving the problems] The above-mentioned problems, especially the conventionally used adhesives, have poor suitability as textile adhesives, heat resistance, water resistance, solvent resistance, hot water washing resistance, and In order to solve the problem that dry cleaning properties are not necessarily satisfactory in all respects, the present invention employs an ionizing radiation-curable polyamide resin as an adhesive for fibers. That is, the present invention provides ethylene at the terminal end of a polyamide resin obtained by reacting a compound having at least one aziridinyl group and at least one group having an ethylenic double bond in one molecule with the terminal carboxyl group of a polyamide resin. The present invention provides an ionizing radiation-curable hot melt adhesive characterized by being made of a polyamide resin having a polyamide double bond. The polyamide resin used in the present invention is (a) a polycondensate of a divalent or higher polycarboxylic acid and a divalent or higher polyamine, or (b) a polycondensate of a divalent or higher polycarboxylic acid and a divalent or higher polyamine. and ε-
It is a polycondensate with lactams such as caprolactam and valerolactam. Examples of the above divalent or higher polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid,
Aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, trivalent or higher aromatic polycarboxylic acids such as trimellitic acid, pyromellitic acid, aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, butanetetra Trivalent or higher aliphatic polycarboxylic acids such as carboxylic acids can be used, but acid anhydrides thereof can also be used. The carboxylic acid component of the polyamide resin used in the present invention may be any combination of one or more selected from the above-mentioned aromatic polycarboxylic acids or their acid anhydrides, aliphatic polycarboxylic acids or their acid anhydrides. It can be used as Further, as the polyamine component of the polyamide resin used in the present invention, 1,2-diaminoethane,
1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, bis-(3-
aminopropyl) ether, 1,2-bis-(3
Examples include aliphatic diamines such as -aminopropoxy)ethane, alicyclic diamines such as piperazine, 1,3-di-(4-piperidyl)propane, 1,4-bisaminopropylpiperazine, and homopiperazine. Furthermore, lactams such as ε-caprolactam, methyl-ε-caprolactam, and valerolactam can also be used as raw materials for the polyamide resin. Polyamide resin can be produced using the above-mentioned components by a known method using a polycondensation catalyst, but since the polyamide resin used in the present invention is used as a fiber adhesive, There must be no oozing during adhesion, and in order to prevent this, it is necessary to increase the molecular weight of the resin. In order to prevent oozing, the viscosity of the resin at the bonding temperature is preferably 10,000 centipoise or more. In order to increase the molecular weight of the resin, it is desirable to carry out the reaction at high temperature and under high vacuum in the polycondensation step. The softening point of the polyamide resin thus obtained is 60 to 150°C. Since adhesives for fibers are often bonded by steam press or heat press, their softening point is preferably 80 to 150°C. The softening point of the adhesive is more preferably 80-140°C, most preferably 80-120°C, since bonding at temperatures higher than 150°C may cause deterioration of the fabric. The softening point of the resin is
Aromatic polycarboxylic acids, aliphatic polycarboxylic acids,
By selecting the composition ratio of aliphatic polyamine, alicyclic polyamine, and lactam, the temperature can be adjusted to the most preferable temperature. The softness of a resin can be measured by its glass transition point, which is preferably below room temperature. If the glass transition point is higher than room temperature, a problem arises in that the texture of the cloth after bonding becomes poor. This glass transition point can also be adjusted to the most preferable temperature by selecting the composition ratio of the carboxylic acid and the like. The terminal of the above polyamide resin is an amino group or a carboxyl group, and the amino group can be modified to a terminal carboxyl group by reacting with an acid anhydride. Examples of acid anhydrides that can be used include aromatic acid anhydrides such as phthalic anhydride and trimellitic anhydride, and cyclic acid anhydrides such as aliphatic acid anhydrides such as succinic anhydride and maleic anhydride. Can be done. The acid value of the terminal carboxyl group unsaturated polyamide resin thus obtained is 10 to 50 KOHmg/
g, the amine value is 0 to 10 KOHmg/g. By reacting this product with a compound having a group having an aziridinyl group and an ethylenic double bond in one molecule, the polyamide resin having an ethylenic double bond at the end of the present invention can be obtained. At this time, as a polymerization inhibitor, for example, hydroquinone, hydroquinone monoethyl ether, t-
Butylhydroquinone, 2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroxytoluene, 2-methylhydroquinone, etc. can be used. Examples of compounds having an aziridinyl group and an ethylenic double bond in one molecule that can be used in the present invention include the following formula () (However, n=1 to 6, m=0 or 1, R ₁ , R ₂ ,
R ₃ and R ₄ are each hydrogen or an alkyl group having 1 to 4 carbon atoms. Specific examples of this include 2-(1-aziridinyl)ethyl acrylate, 2-(1-aziridinyl)ethyl methacrylate, 2-[1-(2
-methylaziridinyl)]ethyl methacrylate,
2-[1-(2,2-dimethylaziridinyl)]
Examples include ethyl methacrylate, 1-(1-aziridinyl)methyl acrylate, 1-(1-aziridinyl)methyl methacrylate, 3-(1-aziridinyl)propyl acrylate, and 3-(1-aziridinyl)propyl methacrylate. The polyamide resin having an ethylenic double bond at the end of the present invention can be produced, for example, as follows. First, a polyamide resin having a terminal carboxyl group is heated and melted at 150 to 240°C, a mixture of aziridinyl (meth)acrylate and a polymerization inhibitor is added dropwise to the resin, and the mixture is stirred at 150 to 240°C for 3 to 5 hours. The softening point and glass transition point of the polyamide resin having an ethylenic double bond at the end of the molecule thus obtained are almost the same as those of the polyamide resin produced in the first step as a prepolymer polyamide. The polyamide resin can be cured by irradiation with ionizing radiation without containing an ionizing radiation-curable monomer or oligomer, but if necessary, an ionizing radiation-curable monomer may be added. It is also possible to add oligomers and oligomers, as long as they do not lose the solid state, which is a desirable property as a hot melt adhesive for fibers. Furthermore, a polymerization inhibitor, antioxidant, ultraviolet absorber, etc. can be added to the ionizing radiation-curable hot melt adhesive of the present invention for the purpose of improving storage stability. Furthermore, when trying to obtain the adhesive in powder form, it may be difficult to crush the resin if the glass transition point of the resin is below room temperature. It can also be added to the resin in a range of 5% by weight. The ionizing radiation-curable hot melt adhesive of the present invention produced as described above has a softening point of 60 to 60.
The temperature is 150℃. Furthermore, the melt viscosity at a temperature 20° C. higher than the softening point is 3,000 to 300,000 centipoise, and a composition with such dynamic properties is suitable as an adhesive for fibers. When bonding cloth using the hot melt adhesive, the method for placing or adhering the adhesive onto the cloth is not particularly limited, and any known method may be used.
When applying in a molten state, existing hot melt applicators and hot melt coaters can be used. When applying in powder form, a powder coating method, a dot coating method, a dielectric coating method, a heat-sensitive coating method, etc. can be used, and it can also be placed on a cloth in the form of a film or a net. When the hot melt adhesive of the present invention is fixed onto a cloth, it can be made to take any shape such as a film, a net, a spider web, a random powder, a dot, a dash, or the like. Although these differences in shape do not affect the effectiveness of curing by ionizing radiation,
When using film or net forms, the adhesive layer
It is desirable that it is 0.5mm or less. Adhesive layer is 0.5
If it exceeds mm, the texture after bonding will be poor, the transmittance of ionizing radiation will be poor, and high energy will be required. The melt bonding method is not particularly limited, and may include heat press bonding, ultrasonic bonding, infrared heat bonding,
Any known method can be used, such as other radio frequency energy bonding methods. By irradiating the adhesive fabric thus obtained with ionizing radiation, the adhesive can be made three-dimensional. Ionizing radiation includes alpha rays,
Examples include β-rays, γ-rays, X-rays, and electron beams, but in consideration of high processing speed, cost reduction, etc., it is most preferable to use electron beams. Furthermore, it is also possible to perform melt adhesion and irradiation with ionizing radiation at the same time. The high voltage generation method for electron beam accelerators is as follows:
Any of the Van de Graaf type, Kotscroft-Walton modified type, insulated iron core type, etc. can be used. As the electron beam accelerator, any of the spot beam scanning type, area beam non-scanning type, and electron curtain type can be used.
The electron beam emitted from such an accelerator has an energy of 100 to 500 keV.
It is preferable to use an irradiation dose in the range of 0.1 to 50 Mrad, and a more preferable irradiation dose is 0.1 to 20 Mrad. Such an electron beam can cure the ionizing radiation-curable adhesive of the present invention to a suitable state. If the electron beam irradiation dose is less than 0.1 Mrad, the formation of crosslinks in the polymer is insufficient;
Improvements in adhesion, heat resistance, solvent resistance, etc. cannot be expected. Furthermore, if the electron beam irradiation dose is greater than 20 Mrad, the polymer crosslink density will increase, resulting in a lack of flexibility, which is a desirable property for textile adhesives, and causing changes in the properties of the fabric itself. There is a fear. A method of irradiating ultraviolet light to cure the adhesive layer after adhesion can be considered, but the ultraviolet curing method requires a sensitizer to be included in the resin, requires long-term ultraviolet irradiation, and only damages the surface layer. It does not harden, it is impossible to promote hardening to the inside, and there is a problem in terms of heat resistance and melting properties. [Examples] The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, "parts" in Examples and Comparative Examples represent "parts by weight" unless otherwise specified. Example 1 (Example of using as an adhesive an acrylic-modified polyamide with an aziridinyl group and an ethylenic double bond at the end) ε-caprolactam 40.5 parts, adipic acid 10 parts,
14 parts of sebacic acid, 16 parts of 1,10-decanedicarboxylic acid
A portion of the solution is placed in a separable flask equipped with a lower funnel, a dehydration tube, a cooling tube, and a stirrer, heated to melt under a nitrogen atmosphere, and heated to 100°C. Thereafter, the heating was stopped, and 19.5 parts of hexamethylene diamine was added dropwise over 2.5 hours. After the dropwise addition was completed, the temperature was raised to 230°C over 5 hours, and stirring was continued at 230°C for 1 hour.
Thereafter, the pressure inside the tank was gradually reduced to 230° C., and the reduced pressure reaction was continued until a predetermined amount of reaction water was distilled out, to obtain a polyamide resin having carboxyl groups at both ends of the molecule. The acid value of the obtained polyamide resin is
The amine value was 44.4KOHmg/g and 0.39KOHmg/g. Add triphenylphosphine 0.1 to this resin at 150℃.
12.7 parts of 2-(1-aziridinyl)ethyl methacrylate dissolved in 0.1 part of 2-methylhydroquinone was added dropwise, and then excess 2-(1-aziridinyl)ethyl methacrylate was removed under reduced pressure. A polyamide resin having an ethylenic double bond at the end of the molecule was obtained. The polyamide resin had a softening point of 105°C, a glass transition point of -2°C, and a melt viscosity of 15,600 centipoise at 130°C. The polyamide resin was molded into a sheet with a thickness of 50 μm, which was sandwiched between Tetoron/cotton (65/35) broadcloth and bonded by thermocompression. Adhesion conditions are temperature
The temperature was 130° C., the pressure was 200 g/cm ² , and the crimping time was 20 seconds. For the adhesive cloth obtained in this way,
NHV Kyuatron (manufactured by Nissin High Voltage Co., Ltd.)
Electron beam irradiation was performed using an accelerating voltage of 200 kV, electron current of 5.4 mA, line speed of 16.7 m/min, and irradiation dose of 3 Mrad to obtain a cured adhesive cloth. This cured adhesive cloth was subjected to a dry cleaning test and a washing test, and then the T-peel adhesive strength was measured. The results are shown in Table 1. The same test was also conducted on the adhesive cloth before electron beam irradiation, and a comparison was made between before and after electron beam irradiation.

[Table] Test details Peeling test: 22℃, tensile speed 100mm/min Dry cleaning test: In Perclean, 25
℃, 10 minute immersion x 5 times Washing test: 10 minute immersion x 5 times in 0.5% flake Marcel soap aqueous solution at 60 ℃ (bath ratio 1:50) As is clear from Table 1, adhesion after electron beam irradiation The adhesive strength of the cloth was improved compared to that before irradiation, and there was hardly any decrease in adhesive strength even after the dry cleaning test and the washing test. In addition, the resin after electron beam curing does not exhibit thermal fluidity,
Softening point was not determined. No oozing of the adhesive due to reheating was observed. Example 2 The acrylic modified polyamide resin having an ethylenic double bond at the end obtained in Example 1 was freeze-pulverized and classified to prepare a powder with an average particle size of 70 μm.
The polyamide resin powder is Tetron/cotton (65/35)
Apply on a broadcloth so that the amount of coating is 20g/ ^m2 .
Dot coating was applied at 20 points/cm ² , and the same type of fabric was layered on top of the dot coating and adhered by thermocompression bonding. The bonding conditions are the same as in Example 1. For the adhesive cloth obtained in this way,
NHV Kyuatron (manufactured by Nissin High Voltage Co., Ltd.)
Electron beam irradiation was performed using an accelerating voltage of 200 kV, electron current of 5.4 mA, line speed of 16.7 m/min, and irradiation dose of 3 Mrad to obtain a cured adhesive cloth. After performing a dry cleaning test and a washing test on these cured adhesive fabrics, the T-peel adhesive strength was measured. The results are shown in Table 2. The same test was also conducted on the adhesive cloth before electron beam irradiation, and a comparison was made between before and after electron beam irradiation. The test conditions are the same as in Example 1.

[Table] Even when the adhesive is applied in a different shape, that is, when the adhesive is applied in dots and bonded, irradiation with an electron beam can
Adhesion, dry cleaning resistance, and water resistance are all improved. Examples 3 to 7 Polyamide resins having carboxyl groups at the molecular terminals were produced by the same method as in Example 1 using the components shown in Table 3. Furthermore, as in Example 1, 2
-(1-aziridinyl)ethyl methacrylate was reacted to produce a polyamide resin having an ethylenic double bond at the end of the molecule.

【table】

[Table] The softening point, glass transition point, and melt viscosity of the obtained polyamide resin having an ethylenic double bond at the end are shown in Table 4 below.

[Table] As shown in Table 4, the resins of Examples 3 to 7 were
All have physical properties suitable as hot melt adhesives for fibers. The resins of Examples 3 to 7 were molded into a sheet with a thickness of 50 μm, which was sandwiched between Tetron/cotton (65/35) broad cloth and adhered by thermocompression bonding. The bonding temperature is
110 in Examples 3, 4, 5, 6, and 7, respectively.
105, 120, 120, 105℃. The pressure during thermocompression bonding was 200 g/cm ² and the bonding time was 20 seconds. For the adhesive cloth obtained in this way,
NHV Kyuatron (manufactured by Nissin High Voltage Co., Ltd.)
Electron beam irradiation was performed using an accelerating voltage of 200 kV, electron current of 5.4 mA, line speed of 16.7 m/min, and irradiation dose of 3 Mrad to obtain a cured adhesive cloth. These cured adhesive fabrics were subjected to a dry cleaning test and a washing test in the same manner as in Example 1, and the T-peel adhesive strength was measured. The results are shown in Table 5. A similar test was also conducted on the adhesive cloth before electron beam irradiation, and a comparison was made between before and after electron beam irradiation.

【table】

[Table] As shown in Table 5, in all of Examples 3 to 7, the adhesive strength was lower after electron beam irradiation than before irradiation.
It can be seen that the adhesive of the present invention has improved dry cleaning resistance and water resistance, and also has a good texture, making it ideal as a hot melt adhesive for textiles. In addition, after electron beam irradiation, Examples 3 to 7
Thermal fluidity of both resins had disappeared, and no deterioration of the bonded area due to reheating of the adhesive cloth or any oozing of the adhesive was observed. Comparative Example 1 (Example using ordinary polyamide resin as adhesive) With the same composition ratio and the same operation as in Example 1,
A polyamide resin having carboxyl groups at both ends of the molecule was obtained. The acid value of the obtained polyamide resin is
44.OKOHmg/g, amine value was 0.5KOHmg/g, softening point was 100°C, and glass transition point was 0°C. This polyester resin was molded into a sheet with a thickness of 50 μm, which was sandwiched between Tetoron/cotton (65/35) broadcloth and bonded by thermocompression. The bonding conditions were the same as in Example 1. The thus obtained adhesive cloth was irradiated with an electron beam under the same conditions as in Example 1. After conducting a dry cleaning test and a washing test on this product, the T-peel adhesive strength was measured. The results are shown in Table 6. The same test was also conducted on the adhesive cloth before electron beam irradiation, and a comparison was made between before and after electron beam irradiation. Comparative Example 2 After adding 1% by weight of benzoin isopropyl ether to the polyamide resin having an ethylenic double bond at the molecular end obtained in Example 1, an adhesive cloth was obtained in the same manner as in Example 1. For this adhesive cloth
Ultraviolet light was irradiated for 10 seconds using a 2KW ultraviolet lamp. This product was subjected to the same dry cleaning test and washing test as in Example 1, and then the T-peel adhesive strength was measured. The results are shown in Table 6. The same test was also conducted on the adhesive cloth before irradiation with ultraviolet rays, and a comparison was made before and after irradiation with ultraviolet rays.

〔Effect of the invention〕

The polyamide resin of the present invention having an ethylenic double bond at the end of the molecule has excellent adhesive strength, solvent resistance, water resistance, and heat resistance, and has appropriate flexibility, so it is suitable for adhesive sewing applications. It can be widely used in For example, it can be used to sew cuffs of short-sleeved shirts, hem hems of skirts, and add names to endpapers. In addition, in terms of ionizing radiation curability, by using electron beams, the adhesive can be cured in a short time, significantly increasing the adhesive processing speed, and greatly streamlining the sewing process. can contribute. Furthermore, since energy can be intensively input to the target object, it is also effective in terms of energy conservation. Furthermore, the resin of the present invention can be used not only for fibers but also for any material that transmits ionizing radiation, and can be applied to bond metals, paper, plastics, wood, etc. It is.

Claims (1)

[Claims] 1 At least one aziridinyl group in one molecule
and a polyamide resin having an ethylenic double bond at the end of the molecule, which is obtained by reacting a compound having at least one group having an ethylenic double bond with a terminal carboxyl group of the polyamide resin. Ionizing radiation-curable hot melt adhesive. 2 At least one aziridinyl group in one molecule
and at least one group having an ethylenic double bond, the compound has the following formula () (However, n=1 to 6, m=0 or 1, R ₁ , R ₂ ,
The ionizing radiation-curable hot melt adhesive according to claim 1, wherein R ₃ and R ₄ are each hydrogen or an alkyl group having 1 to 4 carbon atoms. 3. The ionizing radiation-curable hot melt adhesive according to claim 1, wherein the polyamide resin having an ethylenic double bond has a softening point of 60 to 150°C.