JPH0786159B2 - Hot melt adhesive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot-melt adhesive, particularly a water-soluble hot-melt adhesive useful for temporary fixing of fibers and the like.

[Prior Art] Hot-melt adhesives can be applied to a wider range of adhesion than other adhesives, the adhesion speed is very fast, there is no toxicity or fire hazard, and it is economically advantageous. For this reason, it has been actively used in recent years for applications such as bookbinding, packaging, woodworking, shoemaking, and fabric bonding.

For example, in recent years, the adhesive has been widely used in the sewing of clothing, and when sewing the collar, cuffs, etc. of a shirt, first, the adhesive is applied to the interlining so that the interlining and the outer material do not shift. After temporarily adhering to the outer material, it is cut and sewn.

In such a case, the hot melt adhesive is required to satisfy the following properties: adhesiveness, melt viscosity, heat resistance, cold resistance, flexibility, water removability, and fabric texture. Widely used ethylene-vinyl acetate copolymers, polyethylene, etc. are hydrophobic, so that polyvinyl alcohol-based resins having a low degree of polymerization and a low degree of saponification have recently attracted attention because of their lack of water-solubility and removability. (For example, JP-A-51-88533 and JP-A-51-88533).
-149328, 51-151733, etc.), it can be a good hot melt adhesive as compared with the above resins.

[Problems to be Solved by the Invention] However, in the polyvinyl alcohol resin having a low degree of polymerization and a low saponification degree, in order to keep the melt viscosity as low as possible, the low saponification degree, that is, substantially 50 mol% or less. And low polymerization degree, it is necessary that it is substantially 500 or less, but on the other hand, the adverse effect of lowering the saponification degree may result in a decrease in adhesive strength and blocking resistance, or on the other hand, as described above. Since it is not often necessary to impart water-soluble removal properties, at this time, the saponification degree must be increased to some extent, and deterioration of the melting characteristics and the like cannot be avoided. That is, in the conventionally known low polymerization degree and low saponification degree of polyvinyl alcohol resin, it is very difficult to keep all the physical properties such as adhesive strength, blocking resistance, melting property, water-soluble removability in good balance. It's difficult to do.

[Means for Solving Problems] However, the inventors of the present invention have conducted extensive studies to solve the above problems in polyvinyl alcohol-based resin hot melt adhesives, and as a result, have a polymerization degree of 2,500 or less and a saponification degree of 20 to 95. Hot-melt adhesives composed mainly of polyvinyl alcohol resin with a mol% and blocking character of 0.70 or more can be balanced in various performances, and have a wider degree of polymerization and saponification than before. The inventors have found that they can be used in a range of degrees and completed the present invention.

The polyvinyl alcohol resin used in the present invention must have a block character of 0.70 or more.

Here, the block character, when represented by “η”, is calculated based on the following equation.

η = (OH, OAc) / 2 (OH) (OAc) where (OH, OAc) is measured in the ¹³ C-NMR spectrum. Based on the absorption intensity of the methylene group, that is, (a) to (b) of the peak area of (b) in the amount of the two-unit chain structure (dyad).
(C) The ratio to the total peak area is expressed in mole fraction. Further, (OH) and (OAc) are the vinyl alcohol group content (or saponification degree) and the residual vinyl acetate group content in the polyvinyl alcohol-based resin, respectively, which are expressed in mole fractions.

In the case of polyvinyl alcohol resins that are generally commercially available,
The block character is less than 0.55, and it is difficult to obtain the effects of the present invention with such a resin.

The polyvinyl alcohol-based resin used in the present invention is not particularly limited as to its production method, and can be produced by any method, for example, a method of acid-saponifying polyvinyl acetate,
Examples thereof include a method of reacetylating polyvinyl alcohol.

Further, in the present invention, it is essential to use a polyvinyl alcohol-based resin having a specific block character value of 0.70 or more in the block character among polyvinyl alcohol-based resins having a block character of 0.55 or more obtained by the above method. In the polyvinyl alcohol-based resin, hydroxyl groups and residual vinyl acetate groups are particularly randomly distributed. In this respect, ordinary commercially available polyvinyl alcohol (alkali saponified product) has a large difference between the water group and the residual vinyl acetate group in a block distribution, which is a big difference from the resin of the present application.

The degree of polymerization of the resin is 2,500 or less, preferably 1,5
It is 00 or less, more preferably 100 to 1,500. When the degree of polymerization is more than 2,500, the melt viscosity becomes high, which is not practical.

The degree of saponification is in the range of 20 to 95 mol%, preferably 20 to 85 mol%, more preferably 30 to 75 mol%. Saponification degree is 20
If it is less than 95% by mole, blocking resistance, adhesive strength and water-dissolving removability will be deteriorated, and if it exceeds 95% by mole, melt viscosity will be high and should be avoided.

As described above, in the present invention, by using a polyvinyl alcohol-based resin having a unique block character, a hot melt adhesive having a broader range of performance and a higher degree of polymerization and saponification than conventional ones is obtained. It becomes possible.

The polyvinyl alcohol-based resin is not necessarily limited to the one obtained by saponifying polyvinyl acetate, and may be a polyvinyl alcohol-based resin derivative.

As the derivative, a carbonyl group-containing polyvinyl alcohol, a formal compound of polyvinyl alcohol, an acetal compound, a butyral compound, a urethane compound, a sulfonic acid,
Examples thereof include esterified products with carboxylic acids and cationized products. Further, a saponified product of a copolymer of a vinyl ester and a monomer copolymerizable therewith may be mentioned, and as the monomer, ethylene, propylene, isobutylene, α-octene, α-dodecene, Veova (long-chain alkyl vinyl ester ), Olefins such as α-octadecene, etc., unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, itaconic acid or salts thereof or mono- or dialkyl esters, etc., acrylonitrile, nitriles such as methacrylonitrile, etc., Amides such as acrylamide and methacrylamide, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid or salts thereof, alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, acetoacetyl group Containing Eth Emissions unsaturated monomers, oxyalkylene group-containing unsaturated monomers, the first
Graded, secondary, tertiary amine, quaternary ammonium salt-containing unsaturated vinyl monomers and the like. However, the present invention is not limited to these.

Plasticizers may be used in order to make the heat-melting property and the water-dissolving and removing property more effective. Examples of plasticizers include polyhydric alcohols such as sorbit and mannitol, glycols such as glycerin, diglycerin, ethylene glycol, polyethylene glycol, propylene glycol, and methylpentanetriol, sorbitan aliphatic esters and ethylene oxide adducts. Activator,
Examples thereof include vinyl acetate oligomer. The addition amount is preferably in the range of 1 to 100% by weight based on the polyvinyl alcohol resin.

Further, as an additive that can be added to the adhesive of the present invention, rosins, rosin ester compounds, pinene-based polymers, hydrogenated petroleum resins, and the like, which are compatible with resins, such as tackifiers, antioxidants, fillers, and waxes. And the like, which can be used by adding an appropriate amount.

[Working] The hot-melt adhesive of the present invention is used for temporary adhesion of interlining, for bookbinding (back binding for wireless binding, cover wrapping for cover wrapping, etc.), box making (flap card corrugated seals, etc.), packaging, woodworking It can be used in all conventionally used fields such as shoe manufacturing, but is particularly useful as a temporary adhesive interlining adhesive for sewn garments because of its excellent water-soluble removal property.

[Effect] However, the hot-melt adhesive of the present invention has a wider degree of polymerization and a wider saponification range than conventional polyvinyl alcohol-based resin hot-melt adhesives, as has been repeated. In addition to being able to be used, it is a highly balanced product such as adhesive strength, melt viscosity, heat resistance, cold resistance, flexibility, feeling, water removability, etc., and its industrial advantage is very large. .

EXAMPLES Next, the composition of the present invention will be described in more detail by way of examples. Unless otherwise specified, "%" and "parts" are based on weight.

The conditions for measuring the melting temperature and the melt viscosity of the polyvinyl alcohol resin are as follows.

Equipment used: Koka type flow tester ・ Melting temperature nozzle: 1mmφ × 10mm Load: 40Kg / cm ² Temperature rising rate: 6 ° C / min ・ Melting viscosity nozzle: 1mmφ × 10mm Load: 40Kg / cm ² Temperature: 145 ° C Example 1 Tetoron / cotton mixed 16th yarn, 95 yarns / (inch), and 10th yarn, 50 yarns / (inch)
600, polyvinyl alcohol with a saponification degree of 70 mol% and a block character of 0.78 (melting temperature 119 ° C, melt viscosity 8 × 1
0 ⁴ ps) was sprinkled at a rate of 18 g / m ² and passed through a hot air dryer set at 130 ° C. at a speed of 35 m / min to temporarily bond the hot melt adhesive to the fabric to prepare an interlining. . This interlining was sandwiched between the front and back sides of the georgette fabric of the clothes for women's summer dresses, and heat-pressed for 7 seconds at a pressure of 0.3 kg / cm ² with a household 2 pound iron set to a temperature of 130 ° C.
The peel strength of this adhesive interlining is 350g / with Tetoron / cotton
(Ichi), cotton single yarn was 300g / (Ichi), and the blocking resistance was also good. The above polyvinyl alcohol was produced by the following method.

Charge 100 parts of a 40% methanol solution of completely saponified polyvinyl acetate with a polymerization degree of 600 obtained by a conventional method and 6.84 parts of a 10% sulfuric acid-methanol solution of concentrated sulfuric acid diluted with methanol into a kneader equipped with a reflux condenser. The reaction was started at 60 ° C., and while removing the effluent, the same amount of methanol as the effluent was added and reacted for 4.5 hours, and then 22.87 parts of a 5% sodium acetate aqueous solution was added for neutralization. .

After cooling, the reaction product was dried under reduced pressure at 60 ° C for about 12 hours to obtain a block character of 0.78, a saponification degree of 70 mol% and a polymerization degree of 600.
Of polyvinyl alcohol was obtained.

Next, the three-layered fabric of the front, back cloth and interlining of the georgette was sewn with a sewing machine, swirled with water at 35 ° C. for 15 minutes in a domestic washing machine, and this was repeated twice and then air-dried. The sewn interlining had a peel strength of 0 and was completely desized by washing with water. In addition, the texture of the Georgette fabric was retained.

The above results are summarized in the table.

Examples 2 to 9 Experiments were carried out according to the same example, using the resins shown in the table instead of the polyvinyl alcohol in Example 1.

The results are shown in the table.

However, in Example 8, polyvinyl alcohol modified with 1-dodecene at 1.0 mol% was used, and in Example 9, polyvinyl alcohol modified with sodium allylsulfonate at 2 mol% was used.

As a control example, the same experiment as in Example 1 was conducted except that polyvinyl alcohol having a block character of 0.39 and a commercially available polyvinyl alcohol-based hot melt adhesive were used. Further, as a control example, when the polyvinyl alcohol resin of Example 1 was manufactured, the reaction temperature was set to 40 ° C., and the reaction was performed for 10 hours without adding methanol to obtain a block character.
The same experiment as in the same example was carried out by obtaining polyvinyl alcohol having 0.60, a saponification degree of 70 mol% and a polymerization degree of 600.

The results are also shown in the table.

The evaluation method is as follows.

・ Peeling strength After leaving for 24 hours at 25 ° C, 60% RH, measure peel strength per inch at a pulling speed of 10 cm / min using Shimadzu Autograph S-100 type. ・ Blocking resistance Sample film (thickness Approximately 100μ) 2 pieces are piled up and this is 4
The peeled state was observed after standing at 0 ° C., 65% RH and 50 g / cm ² pressure for 24 hours.

-Water-soluble removal property After washing the interlining after washing with water, the presence or absence of the residual adhesive was observed by the iodine coloration method.

Claims (1)

[Claims] 1. A polymerization degree of 2,500 or less and a saponification degree of 20 to 95 mol%.
A hot melt adhesive whose main component is polyvinyl alcohol resin with a block character of 0.70 or more.