JPH0137433B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a polyamide-based reactive hot melt adhesive. [Prior Art and Problems] Conventionally, many adhesive interlinings have been coated with a polyamide hot melt adhesive in powder form. Polyamide-based hot-melt adhesives have good adhesion to various fabrics and excellent dry cleaning resistance, but on the other hand, they have the drawbacks of being harder and having slightly poorer hot-water washing resistance than polyester-based hot-melt adhesives. are doing.
Another disadvantage is that the adhesive may undergo plastic deformation during repeated ironing, resulting in a hard texture or oozing onto the surface of the fabric. The present inventors have already developed (a) a polyamide-based hot melt adhesive that improves these drawbacks and has excellent hot water washing resistance and ironing resistance, has a soft texture, and can be used for various fiber bonding applications.
A method in which polyamide resin is placed in a reaction pot or kneader, heated and melted at a temperature between the softening point of the resin and the softening point + 30°C, and an alkoxysilane compound having an isocyanate group is added and reacted. (b) Polyamide resin is mixed with dimethylformamide, dimethyl We are developing a polyamide resin that can be obtained by heating and dissolving it in a polar solvent such as acetamide or dimethyl sulfoxide, adding the above alkoxysilane compound at a temperature of 60 to 120°C, and allowing the reaction to occur. However, the hygroscopic crosslinkable polyamide resins produced by these methods have a high denaturation temperature, so some of the alkoxysilyl groups may cause hydrolytic crosslinking during denaturation, or may partially absorb moisture during the powdering process after denaturation. It can be cross-linked to. As a result, it has become clear that there is a problem in that it is difficult to obtain sufficient adhesive force unless the bonding temperature to the fibers is raised. [Means for Solving the Problems] The present inventors have improved on these problems, and have developed a technology that can bond fabrics at lower temperatures without damaging them, and has improved resistance to hot water washing and ironing. As a result of extensive research in order to obtain a polyamide-based hygroscopic crosslinking hot melt adhesive that has an excellent and soft texture and can be used for various fiber bonding applications, we have developed a powdered polyamide resin obtained by a specific method. The present invention was completed based on the discovery that the object of the present invention can be achieved. That is, the present invention combines powder of a polyamide resin having an amino group with (a) an organic liquid containing a hydrolyzable organosilicon compound having an isocyanate group, which does not have active hydrogen and does not dissolve the polyamide resin; (b) A powdery hygroscopic crosslinking hot melt adhesive characterized in that it is dispersed in a liquid hydrolyzable organosilicon compound having an isocyanate group, and the polyamide resin is reacted with the hydrolyzable organosilicon compound. A manufacturing method is provided. The polyamide resin forming the skeleton of the hygroscopic crosslinkable hot melt adhesive of the present invention can be obtained by polycondensation or ring-opening polymerization by a known method. Examples of dicarboxylic acids used in the synthesis of the polyamide resin include adipic acid, β-methyladipic acid, pimelic acid, corkic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. , aliphatic dicarboxylic acids such as eicosandioic acid, dimer acids mainly composed of dicarboxylic acids having 36 carbon atoms, and 2-dodecenylsuccinic acid, isododecenylsuccinic acid, isododecylsuccinic acid, isooctylsuccinic acid, n
- Octylsuccinic acid, etc. and their acid anhydrides, terminally carboxylated liquid rubbers such as terminally carboxylated 1,2-polybutadiene, terminally carboxylated hydrogenated 1,2-polybutadiene, and aromatic dicarboxylic acids such as isophthalic acid. . Diamines used in the synthesis of the polyamide resin of the present invention include propylene diamine, 1,2-
Diaminopropane, tetramethylenediamine, piperazine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,
8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, molecular weight 300-2000
Examples include polyethylene glycol diamine which is aminated at both ends. It is also possible to use lactams having 6 to 12 carbon atoms such as ε-caprolactam and ω-lauryllactam, or their ω-amino acids. A polyamide resin having amino groups can be obtained by making the number of moles of diamine charged among the above raw materials slightly larger than the number of moles of dicarboxylic acid charged. The number average molecular weight of the polyamide resin used in the present invention is 2000 to 20000, more preferably 4000 to 20000.
Preferably 12000. If the number average molecular weight is too small, it is not preferable because it will cause problems such as excessive penetration into clothing, deterioration of appearance due to seepage to the opposite side, and insufficient initial adhesive strength. On the other hand, if the number average molecular weight is too large, it is undesirable because the wettability to the adherend becomes poor, the crosslinking density decreases, making it impossible to obtain sufficient heat and pressure bonding resistance, and causing problems in dry cleaning resistance. . The hydrolyzable organosilicon compound having an isocyanate group used in the present invention is preferably one represented by the following general formula (). However, R ¹ is an unsubstituted or substituted hydrocarbon group selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and in the hydrocarbon chain -NHCONH- or -NHCOS- It does not matter if it contains foreign elements such as. R ² is a methyl group or an ethyl group, X is a hydrolyzable functional group, a
is 0 or 1 or 2. X is an alkoxy group such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group, methoxyethoxy group, acyloxy group such as acetoxy group, octanoyloxy group, benzoyloxy group, propenoxy group, isopropoxy group, 5,5- Alkenoxy groups such as dimethylcyclohexan-1-one-3-yloxy groups, N,N-dimethylamino groups, N,N
- N,N-substituted amino groups such as diethylamino group, N,N-methylethylamino group, N,N-methylcyclohexylamino group, ketoxime such as dimethylketoxime group, methylethylketoxime group, diethylketoxime group, butanoxime group, etc. Base, N,
Aminoxy groups such as N-dimethylaminoxy group, N,N-methylethylaminoxy group, N,N-diethylaminoxy group, N-methylacetamide group,
Examples include amide groups such as N-ethylacetamide group, N-butylacetamide group, and N-benzylacetamide group. The hydrolyzable functional group preferably used in the present invention is an alkoxy group. Examples of alkoxysilane compounds represented by the general formula () are 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropylmethyldiethoxysilane. Examples include silane. In addition, alkoxysilane compounds containing bonds such as -NHCONH- or NHCOS- include hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, lysine diisocyanate, and trimethylhexamethylene. It is obtained by an addition reaction between a diisocyanate compound such as diisocyanate or xylylene diisocyanate and a terminal amino or terminal mercaptoalkoxysilane compound such as 3-aminopropyltriethoxysilane or 3-mercaptopropyltrimethoxysilane. Examples of organic liquids that do not have active hydrogen and do not dissolve the polyamide resin used in the present invention include low molecular weight hydrocarbons such as n-hexane, heptane, and liquid paraffin, ketones such as acetone and methyl ethyl ketone, benzene, toluene, and xylene. aromatic hydrocarbons, methylene chloride, chloroform,
Examples include, but are not limited to, chlorinated solvents such as carbon tetrachloride, trichlorethylene, and perchlorethylene. The powdered hygroscopic crosslinkable hot melt adhesive of the present invention is produced as follows. First, the polyamide resin synthesized by the above method is cooled with liquid nitrogen, and mechanically crushed at a temperature below the glass transition point of the polyamide resin to a particle size of 500 microns or less.
More preferably, the powder is 200 microns or less.
The polyamide resin powder thus obtained is vacuum-dried or hot-air dried to adjust the moisture content in the powder to 0.4% or less, more preferably 0.2% or less. The polyamide resin powder, the hydrolyzable organosilicon compound represented by the general formula (), and, if necessary, the above-mentioned organic liquid are charged into a reaction vessel and maintained at a temperature between room temperature and the boiling point of the liquid components to produce the hydration. The decomposable organosilicon compound penetrates not only the surface but also the inside of the polyamide resin powder and bonds with the amino groups of the polyamide molecules with urea to form the desired modified polyamide resin. In this reaction, the polyamide resin powder is neither dissolved in the hydrolyzable organosilicon compound nor in the organic liquid added as a dispersion medium, and the initial particle shape is maintained even after the reaction. After the reaction is completed, the liquid component is filtered out and the powder component is vacuum-dried at a temperature of room temperature to 50°C, more preferably room temperature to 40°C, to obtain a powdery hygroscopic crosslinkable hot melt adhesive. The bonding ratio (denaturation rate) of the hydrolyzable organosilicon compound represented by the general formula () to the amino group of the polyamide molecule varies from 1 to 100% depending on the reaction temperature, reaction time, and concentration of the hydrolyzable organosilicon compound.
It can be adjusted freely within the range. According to the method of the present invention, the modification reaction can be carried out at a lower temperature than the method previously developed by the present inventors. For this reason, a side reaction occurs during modification, in which a small amount of water in the reaction system acts on the -Si-X _3-a group bonded to the polyamide molecule and hydrolyzes it to produce a silanol group, followed by dehydration condensation between molecules. The crosslinking reaction that causes intermolecular crosslinking can be suppressed to a low level. As a result, it is possible to lower the temperature of the hot melt adhesive to the same level as the bonding temperature of unmodified polyamide. The hygroscopic crosslinking hot melt adhesive of the present invention contains tin octylate in the resin for the purpose of promoting the crosslinking reaction.
Organotin compounds such as dibutyltin dilaurate, dioctyltin malate, dioctyltin oxide,
Organic titanium compounds such as tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetraisopropylbis(dioctylphosphite) titanate, and tetraoctylbis(ditridecylphosphite)titanate may be added in an amount of 0.01 to 3% by weight. You can also do it. The softening temperature of the powdered hygroscopic crosslinking hot melt adhesive of the present invention is 60 to 160°C, more preferably
The temperature is preferably within the range of 80 to 130°C. If the softening temperature is too low, the fluidity of the powder will deteriorate, and even after the crosslinking reaction due to siloxane bonds has progressed, plastic deformation of the resin will occur every time the thermocompression bonding is repeated, such as by ironing or hot pressing, causing the bonded clothing to deteriorate. This is not preferable because it causes a change in texture. If the softening temperature is too high, the adhesion temperature to clothing must also be made even higher, which is undesirable because the fibers tend to shrink or discolor. In order to improve the fluidity of the hygroscopic crosslinkable hot melt adhesive powder of the present invention, inorganic fine powder such as silicon oxide or titanium oxide may be added in an amount of 0.05 to 5% based on the powder. The moisture-absorbing crosslinking hot melt adhesive of the present invention can be kept dry and sealed so that the moisture content is 0.3% or less, more preferably 0.1% or less, so that the progress of the crosslinking reaction during storage can be suppressed and it can be stored for a long time. is possible. The hygroscopic crosslinking hot melt adhesive of the present invention has a hydrolyzable organosilicon functional group introduced into the polyamide molecular chain that is hydrolyzed by moisture in the air or moisture in the adherend and converted into a silanol group. A crosslinked structure is created by causing a dehydration condensation reaction between molecules to form siloxane bonds. When the adherend has a hydroxyl group, it is thought that a siloxane bond is formed with the adherend. The crosslinking reaction is accelerated at higher temperatures. Humidification using steam or the like is not necessarily necessary. If too much moisture is supplied, a layer of water will form at the bonding interface, the bonding temperature will drop, or water will rapidly evaporate due to the heat during bonding, creating stress for peeling in the bonded area, which is undesirable. . [Examples] The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. Example 1 ε-caprolactam 3564.5 parts by weight (45.0 mol%) Adipic acid 912.5 〃 (8.92 〃) Decanedicarboxylic acid 1438.0 〃 (8.92 〃) Eicosandioic acid 2018.7 〃 (8.92 〃) were charged into a separable flask and degassed under reduced pressure. After repeatedly replacing the inside of the system with a nitrogen atmosphere, the temperature was raised, and when the raw materials in the system were melted and stirring became possible, the temperature was further increased while dropping 2297.2 parts by weight (28.24 mol%) of hexamethylene diamine. . After the dropwise addition of hexamethylene diamine was completed and the distillation of condensed water began, nitrogen was started to flow slowly, the temperature was raised to 230°C, and the reaction was continued for 1 hour under normal pressure. and 50~70mm
The pressure was reduced to Hg and the reaction was carried out for 1 hour to obtain a copolyamide resin. The acid value of the polyamide resin is
0.86KOHmg/g, total amine value 13.5KOHmg/g,
The softening temperature was 115°C. The softening temperature is determined by preheating at 80°C for 1 minute using a Shimadzu flow tester, then increasing the temperature at 6°C/min under a load of 20 kg/cm ² , when the resin powder melts into a rubber-like state. This is the temperature at which The polyamide resin was cooled with liquid nitrogen, freeze-pulverized into a powder with an average particle size of 40 microns, and then vacuum-dried at 30°C to obtain a dry powder with a moisture content of 0.1%. 100 parts by weight of the polyamide resin powder and 100 parts by weight of 3-isocyanatopropyltriethoxysilane were placed in a separable flask, left standing at 35°C for 3 days, filtered, washed with n-hexane, and heated to 30°C. The mixture was vacuum dried for one day to obtain a powder of a hygroscopic crosslinking hot melt adhesive. Table 1 shows the properties of the moisture-absorbing crosslinking hot melt adhesive powder. Further, the durability of the cloth bonded with the adhesive is shown in Table 2. Example 2 100 parts by weight of the polyamide resin powder prepared in Example 1, 80 parts by weight of n-hexane, and 20 parts by weight of 3-isocyanatopropyltriethoxysilane were charged into a separable flask and stirred at 60°C for 12 hours. The mixture was filtered, washed and dried in the same manner as in Example 1 to obtain a powdery hygroscopic crosslinkable hot melt adhesive.
The properties of the adhesive are shown in Tables 1 and 2. Example 3 ε-caprolactam 2829.0 parts by weight (25.0 mol%) Adipic acid 1753.7 〃 (12.0 〃 ) Decanedicarboxylic acid 2763.6 〃 (12.0 〃 ) Isophthalic acid 1993.7 〃 (12.0 〃 ) Hexamethylenediamine 4532.2 parts by weight (39 .0 mol%) A polymerization reaction was carried out in the same manner as in Example 1 at the ratio of
A copolyamide resin having a softening temperature of 98° C. was obtained. The polyamide resin was powdered in the same manner as in Example 1 and dried to give an average particle size of 52 microns and a water content of 0.15%.
powder was prepared. 100.0 parts by weight of the polyamide resin powder, 80.0 parts by weight of n-hexane, Pour 20.0 parts by weight into a separable flask and heat at 25°C.
After soaking for 48 hours, the mixture was filtered, washed, and dried in the same manner as in Example 1 to obtain a powdery moisture-absorbing crosslinking hot melt adhesive. The properties of the adhesive are shown in Tables 1 and 2. Comparative Example 2,800 parts by weight of the polyamide resin synthesized in Example 1 was charged into a 3-kneader, melted at 130°C, and 88.2 parts by weight of 3-isocyanatopropyltriethoxysilane was added for 5 minutes while stirring at a speed of 60 revolutions per minute. The mixture was added dropwise and kneaded for 10 minutes to perform a modification reaction. The modified polyamide resin thus obtained was freeze-pulverized to obtain a hygroscopic crosslinkable hot melt adhesive powder with an average particle size of 40 microns. Table 1 shows various properties of the powder in comparison with those of Example 1.

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〔Effect of the invention〕

Thus, the moisture-absorbing crosslinking hot melt adhesive of the present invention exhibits short-term thermal adhesive properties characteristic of hot melt adhesives and permanent adhesive properties such as excellent solvent resistance and heat resistance due to the formation of crosslinks. Furthermore, the effect of the soft segment in the copolyamide skeleton can impart a soft feel to the bonded clothing. Furthermore, since this adhesive powder hardly causes any cross-linking reaction during the manufacturing process, there is no need to raise the bonding temperature, and the fabric can be bonded without causing thermal damage.

Claims (1)

[Scope of Claims] 1. A powder of a polyamide resin having an amino group is mixed with (a) an organic liquid containing a hydrolyzable organosilicon compound having an isocyanate group, which does not have active hydrogen and does not dissolve the polyamide resin, or (b) A powdery hygroscopic crosslinkable hot melt adhesive characterized by being dispersed in a liquid hydrolyzable organosilicon compound having an isocyanate group and causing the polyamide resin and the hydrolysable organosilicon compound to react. manufacturing method.