JP3527547B2 - Polyvinyl alcohol resin composition and use thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl alcohol resin composition which has a low melting point and a low melt viscosity at low temperature and is excellent in coating workability, and also has excellent adhesiveness under heat and humidity resistance. More specifically, the present invention relates to a polyvinyl alcohol-based resin composition suitable for a water-soluble or water-dispersible hot melt adhesive that can be recycled, and its use.

[0002]

2. Description of the Related Art Hot-melt adhesives can be applied to a wide range of adherends, have a very high adhesion speed, have no toxicity or danger, and are economically advantageous, as compared with other adhesives. For reasons such as bookbinding, packaging, woodworking,
It is widely used for making shoes and adhering fabrics. The hot-melt adhesive is required to meet performances such as adhesiveness, meltability, heat resistance, cold resistance and flexibility, and is generally an ethylene-vinyl acetate copolymer, polyethylene, polypropylene, polyamide, polyester. Are used as base polymers, especially for bookbinding,
Hot-melt adhesives based on ethylene-vinyl acetate copolymer, which has excellent adhesiveness, workability and flexibility, are widely used for applications such as bag making, packaging, paper tubes, and labels. . However, since the adhesive is hydrophobic, for example, when recycled processing of waste paper, a portion that does not dissolve or disperse in water remains and the processing becomes difficult. Therefore, recently, polyvinyl alcohol resin that is water-soluble is used. Hot-melt adhesives are becoming the focus of attention.

However, since polyvinyl alcohol resins have high melting points and high melt viscosities at low temperatures, they are not suitable as hot-melt adhesives alone, and glycerin, ethylene glycol, etc. can be used for these resins. However, it is impossible to reduce the melting point and the melt viscosity to the target only by adding such a plasticizer, and the hot-melt adhesive made of the resin is unavoidably high temperature ( There is no choice but to use it at 180 ° C or higher).
When melted in such a high temperature range, the polyvinyl alcohol-based resin is prone to thermal decomposition, and the compatibility of the polyvinyl alcohol-based resin with various additives in hot melt adhesives that are normally used tends to decrease. There is. Therefore, in order to achieve both thermal meltability and water solubility, a polyvinyl alcohol resin and an ethylene-vinyl acetate copolymer (EV
A) in combination (Japanese Patent Publication No. 58-8434, Japanese Patent Publication No. 54)
No. 39017) has been proposed.

[0004]

However, the technology disclosed in Japanese Patent Publication No. 58-8434 has a description of the softening point (melting point) and the melt viscosity. Yes, it is still not satisfactory in terms of actual use.
The softening point of the technology disclosed in Japanese Patent Publication No. 7 is 115 ° C to 13 ° C.
Relatively high at 0 ℃ and melt viscosity at 180 ℃ 4000cps
It is as high as ~ 5000 cps, which is not yet at a satisfactory level, and there is room for improvement. Further, in these disclosed technologies, the adhesiveness at the time of wet heat is not considered, the melt viscosity is low, and the adhesiveness against wet heat is excellent. A hot melt adhesive made of polyvinyl alcohol resin is desired.

[0005]

As a solution to this problem, a polyvinyl alcohol resin composition comprising a hydrophilic polyvinyl alcohol resin, a hydroxy fatty acid having 6 or more carbon atoms or its derivative, and a plasticizer was first applied ( Japanese Patent Application No. 6-43214), however, the present inventor further conducted earnest studies for the purpose of improving coating workability by lowering the molten clay, and as a result, the degree of saponification was 30 to 90 mol% A polyvinyl alcohol-based resin composition comprising a polyvinyl alcohol-based resin (A), a hydrophobic resin (B), and a hydroxy fatty acid having 6 or more carbon atoms or a derivative thereof (C),
The inventors have found that they meet the above-mentioned object and completed the present invention. The greatest feature of the present invention is that a hydrophobic resin and a hydroxy fatty acid having 6 or more carbon atoms are blended, and such a resin composition sufficiently lowers the melting point and the melt viscosity in the low temperature range to improve the coating workability. At the same time, we succeeded in improving the adhesiveness when wet. Hereinafter, the present invention will be described in detail.

As the hydrophilic polyvinyl alcohol resin (A) in the present invention, a polyvinyl alcohol resin which is made water-soluble or water-dispersible by partial saponification or introduction of a hydrophilic group is used. Such a polyvinyl alcohol resin is usually produced by a known method, and the resin is not only a partially saponified product of polyvinyl acetate but also a monomer copolymerizable with a vinyl ester, such as ethylene, propylene, isobutylene, α. -Octene, α-
Dodecene, α-octadecene and other olefins, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid and other unsaturated acids or salts thereof or mono or dialkyl esters, etc., acrylonitrile, methacrylonitrile, etc. Nitriles, 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, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, Dimethyldiallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether Polyoxyalkylene (meth) allyl ether such as Le, polyoxyethylene (meth)
Acrylates, polyoxyalkylene (meth) acrylates such as polyoxypropylene (meth) acrylate,
Polyoxyethylene (meth) acrylamide, polyoxyalkylene (meth) acrylamide such as polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether,
Examples thereof include saponified copolymers with polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine and the like.

Of the above-mentioned monomers, although not particularly limited, a sulfonic acid group-containing monomer and a (poly) oxyalkylene group-containing monomer are particularly preferably used as a monomer having a hydrophilic group. The polyoxyalkylene has a condensation degree of 1 to 300, particularly 3 to 50, and the copolymerization ratio of the monomer having a hydrophilic group is 0.1 to 30 mol%, preferably 1 to 20 mol%. Is suitable. If the copolymerization ratio is less than 0.1 mol%, sufficient water solubility or water dispersibility cannot be obtained, and 3
If it exceeds 0 mol%, the adhesive strength tends to decrease.
The polyvinyl alcohol resin may be used alone or in combination of two or more.

[0008] Ke down degree 必to be 30 to 90 mol% of a hydrophilic polyvinyl alcohol-based resin of the present invention (A)
In principal, good Mashiku at 40 to 80 mol%, the saponification degree 3
If it is less than 0 mol%, the blocking property is large and it becomes insoluble in water. On the contrary, if it exceeds 90 mol%, the melting point of the resin becomes high.
It The average degree of polymerization of the hydrophilic polyvinyl alcohol resin (A) is preferably 50 to 600, more preferably 1
When the average degree of polymerization is from 00 to 500 and the average degree of polymerization is less than 50, the adhesive strength when used as a hot melt adhesive is lowered, and conversely, when it exceeds 600, the melt viscosity tends to increase, which is not preferable.

The hydrophobic resin (B) in the present invention is not particularly limited, but has a softening point (measured by the ring and ball method) of 50.
The viscosity at 150 to 150 ° C. and the viscosity at 160 ° C. (measured by a Brookfield viscometer) is preferably 5000 cps or less, more preferably 70 to 1 as the softening point.
Viscosity at 30 ° C and 160 ° C is 4000 cps
When the softening point is less than 50 ° C., the solidification property of the hot melt adhesive is lowered, and when it exceeds 150 ° C., the viscosity in the low temperature range tends to be high, which is not preferable. Further, when the viscosity at 160 ° C. exceeds 5000 cps, the viscosity as a hot melt adhesive tends to increase, which is not preferable.

Specific examples of the hydrophobic resin (B) include ethylene-vinyl acetate copolymers, phenol resins, styrene resins, polyester resins, polyamide resins and the like, among which vinyl acetate is contained. Quantity is 10
Melt flow index (MFI) of 1 at 50% by weight
Ethylene-vinyl acetate copolymer of 00 to 5000 g / 10 minutes (210 ° C, load of 2160 g), phenolic resin which is a condensate of phenol and formalin, molecular weight is 1
A styrene resin of 500 or less is preferably used. The blending amount of the hydrophobic resin (B) is not particularly limited, but is preferably 10 to 50 parts by weight, more preferably 1 part by weight with respect to 100 parts by weight of the hydrophilic polyvinyl alcohol resin (A).
When the amount is 5 to 45 parts by weight and the amount is less than 10 parts by weight, the compounding effect cannot be exhibited sufficiently, and conversely, when it exceeds 50 parts by weight, the resin composition tends to lose water solubility or water dispersibility, which is not preferable.

[0011] As the number of 6 or more hydroxy fatty acid or a derivative thereof carbon (C) in the present invention are 2-hydro carboxymethyl <br/> -2-methylpentanoic acid, 2-hydro carboxymethyl-5-methyl hexanoic acid, 3-hydro Xy-2-methylpentanoic acid, 8
- hydro carboxy tetradecane acid, 11 hydro carboxy tetradecane acid, 10 hydro carboxy hexadecanoic acid, 11 human
Mud carboxymethyl hexadecanoic acid, 14-hydro carboxy hexadecanoic acid, 12-hydro Kishidodekan acid, 16 hydro carboxy hexadecanoic acid, 12-hydro carboxy octadecanoic acid, 9
- hydro carboxymethyl octadecanoic acid, 22-hydro Kishidokosan acid and alkali salts thereof, ester and the like, in particular 8-hydro carboxy tetradecane acid, 10 hydro <br/> carboxymethyl hexadecane acid, 12-hydro alkoxy octadecanoic acid preferably, in particular 12-hydro alkoxy octadecanoic acid practical. The present invention is characterized by using the hydroxy fatty acid having 6 or more carbon atoms as described above. With the hydroxy fatty acid having 5 or less carbon atoms, the effect as in the present invention cannot be obtained, and tack occurs at room temperature, resulting in adhesion. Power also decreases.

The blending amount of the hydroxy fatty acid or its derivative (C) is not particularly limited, but it is 10 to 100 parts by weight of the hydrophilic polyvinyl alcohol resin (A).
It is preferably 60 parts by weight, more preferably 15 to 50 parts by weight, and if the amount is less than 10 parts by weight, the compounding effect cannot be exerted so much. It is not preferable because it tends to lose its properties.

In the present invention, the effects of the present invention can be sufficiently obtained with only the components (A) to (C).
It is also advantageous to further blend a plasticizer (D) for the purpose of further improving flexibility and the like, and as the plasticizer (D),
There is no particular limitation as long as it is a compound having a plasticizing effect on the hydrophilic polyvinyl alcohol resin (A). For example, glycerin, diglycerin, polyglycerin, pentaerythritol, pentamethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, Examples thereof include polyhydric alcohols such as tetraethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, methylpentanetriol, sorbitol and mannite, and urea derivatives such as ethylene urea.

The blending amount of the plasticizer (D) is not particularly limited, but the hydrophilic polyvinyl alcohol resin (A) is used.
The amount is preferably 10 to 40 parts by weight, more preferably 15 to 35 parts by weight, and if the amount is less than 10 parts by weight, the plasticizing effect cannot be exhibited so much, and if it exceeds 40 parts by weight, the resin is The composition tends to be tacky at room temperature, which is not preferable.

The above (A) to (C) or (A) to obtain the polyvinyl alcohol resin composition of the present invention.
The blending method of (D) is usually well known, that is, using a melter equipped with a stirrer, an extruder, a roll kneader, or the like for melt mixing. The order of blending is not particularly limited, but when a melting can is used, it is usually preferable to add the melting can first from the one having a low melt viscosity in terms of the mixing property. The melt mixing temperature is preferably about 120 to 180 ° C. Such a resin composition is a known compound for hot melt adhesives such as other compounds within a range not impairing the gist of the present invention, for example, rosins, rosin esters, pinene-based polymers, hydrogenated petroleum resins, hydrocarbon resins and the like. Various additives such as additives, antioxidants, lubricants, fillers, colorants, fragrances and stabilizers can be blended.

The resin composition is melt-blended and then molded into an arbitrary shape to obtain a product. For example, in order to commercialize it as a hot melt adhesive, any conventional method can be carried out, and it can be processed into an appropriate shape such as a block, a strip, a biscuit, a pellet, a rope, a powder or a film. The molding method depends on the shape. For example,
In the case of forming into a strip shape, the melt obtained by melting and mixing as described above is caused to flow out from a feeder onto a belt plate such as stainless steel, and cooling water is sprayed from the inside of the belt to cool and solidify the strand discharged indirectly, After solidification, a method of cutting into a strip shape with a cutter and molding can be mentioned. The hot-melt adhesive thus obtained has a low melting point, and since the melt viscosity in the low temperature range is low, it is extremely excellent in coating work, and furthermore, it is conventionally used for the production of ethylene-vinyl acetate copolymers, etc. Since the coating machine can be used as it is, it is industrially very advantageous.

There is no particular limitation on the adherend of the hot-melt adhesive, and it is used for making or sealing cardboard boxes or carton boxes, for packaging pharmaceuticals, confectionery, toys, copy paper, etc.
For bookbinding (wireless binding) of telephone books, catalogs, slips, etc., for bag making such as top / bottom / body attachment, for paper products such as cardboard pallets, fiber cans, paper tubes, labels, etc. For sanitary materials such as paper diapers For woodworking such as assembling furniture and shelves, for making aluminum and polypropylene cans, for building aluminum sashes and for attaching decorative paper on the ceiling, for shoes such as folding and bottoming, oil filters and headlamps. For automobiles, etc.
Used for clothing such as hem of coats, pasting and reinforcement of leather or fabric, electrical parts such as temporary fixing of TV yoke and speaker coil, and general work such as DIY carpentry and other repairs. As a paper product using the hot-melt adhesive, a book bound, a paper bag having an adhesive layer formed thereon, a sealed box, a paper tube made from a tube, a heat-sensitive tape provided with an adhesive layer, or Labels, rewetting tapes or label products can be mentioned. The production of these paper products is carried out according to a conventional method, and a roll known as a method for applying the adhesive,
It is performed by a hot melt coating machine such as a die, a nozzle, and a lip. Although the hot melt adhesive has been described above, the resin composition of the present invention is not only a hot melt adhesive, but also a molded product such as a bottle, a film, a sheet, a hose, a tube, a container, a bag, a fiber, a foam, and the like. It can also be used for various purposes such as paper processing agents.

[0018]

[Working] The resin composition of the present invention has a low melting point and a low melt viscosity in a low temperature range, is excellent in a uniform coating property in a conventional hot melt coating machine, and is also excellent in an adhesive property at the time of moist heat. It is effective as a water-soluble or water-dispersible hot melt adhesive, and a book bound using the hot melt adhesive, a paper bag having an adhesive layer formed thereon, a sealed box, a tube made of paper It is very useful for paper products such as heat-sensitive tapes or labels provided with an adhesive layer, rewetting tapes or labels, etc., especially paper products that require recycling of used paper.

[0019]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, "part" and "%" are based on weight unless otherwise specified. Example 1 Resin composition 100 parts of polyvinyl alcohol (A) having a saponification degree of 65 mol% and an average degree of polymerization of 250, and a vinyl acetate content of 28.
% Melt flow index (MF1) is 2300 g /
20 parts of 10 minutes ethylene-vinyl acetate copolymer (B),
12-hydro carboxymethyl octadecanoic acid (C) 25 parts of glycerin (D) were charged 25 parts of the melt can, to obtain a resin composition of the present invention by melt mixing at 0.99 ° C.. The melting point and melt viscosity of this resin composition were measured in the following manner. (Melting point) Using a PERKIN-ELMER DSC-7 (manufactured by PERKIN-ELMER), the temperature was measured at a temperature rising rate of 20 ° C / min. (Melt viscosity) According to JAI-7-991, using a Brookfield type rotational viscometer, spindle NO. 29, rotation speed 100
The melt viscosity at 140 ° C. and 170 ° C. was measured at rpm.

Hot Melt Adhesive The melt obtained by the above composition was cast in a strand form from a feeder onto a steel belt, and cooling water was sprayed from the inside of the steel belt to cool and solidify the strand. Then, the strand (width 20 mm, thickness 3 mm) was peeled off from the belt and cut into a strip having a length of 20 mm by a rotary cutter. The wet heat adhesiveness and water solubility of the hot melt adhesive were measured as follows. (Wet heat adhesiveness) The above hot melt adhesive is heated and re-melted at 170 ° C., and K liner cardboard (50 × 100 m
m) was coated in a beat shape (0.03 g / cm), and then another K liner cardboard (50 × 50 mm) was bonded under the conditions of open time 2 seconds, set time 5 seconds and load 2 kg / 5 cm, After leaving at 20 ° C and 65% RH for 24 hours,
The adhesion test piece was held vertically under the conditions of 40 ° C. and 80% RH, and a load of 300 g (vertical shearing force) was applied to the smaller corrugated board, and the time until the adhesive layer was broken and dropped was measured. .

(Water-soluble) A rectangular sample of 0.5 g was sampled from the strip-shaped hot-melt adhesive obtained above, and the temperature was kept at 20 ° C. for 1 hour.
It was put in 00 ml of water (using a beaker of 100 cc) and stirred with a magnetic stirrer at about 300 rpm, and the state after 1 hour was examined. The evaluation criteria are as follows. ○ −−− Dissolved or completely dispersed △ −−− Partially dissolved × −−− Almost original shape retained

Examples 2 to 7 and Comparative Examples 1 to 3 As shown in Table 1, resin compositions were produced according to Example 1 by changing the composition of components (A) to (D), and Example 1 It evaluated similarly to. Table 2 shows the evaluation results of Examples and Comparative Examples.

[Table 1] Note) (A) of Example 5 is 1 mol% modified with sodium allylsulfonate. (A) of Example 6 is 3 mol% modified with oxyethylene having a condensation degree of 15. Example 7 is 40 mol% of saponification average. 65 parts by weight of polyvinyl alcohol resin with a degree of polymerization of 200 is used together

In Comparative Example 3 (A), the abbreviations of the unmodified polyvinyl alcohol resin composition used are as follows. SV: saponification degree (representing mol%), P: average degree of polymerization, EVA: vinyl acetate content 28% and MFI 2300
g / 10 min ethylene-vinyl acetate copolymer (softening point 70 ° C., viscosity at 160 ° C. 3500 cp
s) TP; terpene phenolic resin having a molecular weight of 750 (softening point 100 ° C., viscosity at 160 ° C. 500 cp
s, Yasuhara Chemical Co., Ltd., trade name; YS Polystar T
-100) ST: Styrenic resin having a molecular weight of 700 (viscosity at a softening point of 120 ° C. and 160 ° C. of 3000 cp)
s, manufactured by Toho Chemical Industry Co., Ltd., trade name: Hairejin RS-2 1
) 12-hydro xylene; 12-hydro carboxymethyl octadecanoic acid, 8-hydro alkoxy; 8 hydro carboxy tetradecane acid, PEG; polyethylene glycol (molecular weight 300)

[0024]

[Table 2] Melting point Melt viscosity (cps) Wet heat adhesion Water solubility (° C) 140 ° C 170 ° C (hour) Example 1 80 5800 2000> 72 ○ 〃 2 80 5500 1600> 72 ○ 〃 3 86 6000 2000> 72 ○ 〃 4 83 5800 1900> 72 ○ 〃 5 76 5700 1800> 72 ○ 〃 6 75 5500 1500> 72 ○ 〃 7 82 5900 1800> 72 ○ Comparative Example 1 95 9000 4200 5 ○ 〃 2 8 ○ 9 75 5600 1600> 72 x As is clear from the results in Table 2, the polyvinyl alcohol-based resin composition of the present invention has a low melt viscosity at 140 ° C and 170 ° C and is excellent in coating workability, and as a hot melt adhesive. It has excellent adhesiveness when wet and heat, and is very useful as an adhesive for various paper products.

[0025]

Industrial Applicability The resin composition of the present invention has a low melting point and a low melt viscosity in a low temperature range, is excellent in uniform coatability in a conventional hot melt coater, and is also excellent in adhesiveness during wet heat, , Which is effective as a water-soluble or water-dispersible hot melt adhesive, and is bound by using the hot melt adhesive, a book bound, a paper bag in which an adhesive layer is formed, a sealed box, a tube-made paper It is very useful for heat sensitive tapes or labels provided with tubes and adhesive layers, rewetting tapes, labels, etc., especially for paper product applications requiring recycling of used paper.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI C09J 129/04 C09J 129/04 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 29/04 C08K 5/09 C08L 23/08 C08L 25/00 C08L 61/06 C09J 129/04

Claims (10)

(57) [Claims] 1. A hydrophilic polyvinyl alcohol resin (A) having a saponification degree of 30 to 90 mol%, a hydrophobic resin (B) and a hydroxy fatty acid having 6 or more carbon atoms or a derivative thereof (C). A characteristic polyvinyl alcohol-based resin composition. 2. The polyvinyl alcohol resin composition according to claim 1, further comprising a plasticizer (D). 3. The softening point of the hydrophobic resin (B) is 50 to 150.
The polyvinyl alcohol resin composition according to claim 1 or 2, wherein the clay at 60 ° C and at 160 ° C is 5000 cps or less. 4. The hydrophobic resin (B) is at least one selected from ethylene-vinyl acetate copolymers, phenol resins and styrene resins.
The polyvinyl alcohol-based resin composition according to any one of 3 to 3. 5. The average degree of polymerization of the hydrophilic polyvinyl alcohol-based resin saponification degree of 30 to 90 mol% (A) 50
It is -600, The polyvinyl alcohol-type resin composition in any one of Claims 1-4 characterized by the above-mentioned. 6. A hydrophilic polyvinyl alcohol resin (A) having a saponification degree of 30 to 90 mol% contains a hydrophilic group of either a sulfonic acid group or an oxyalkylene group. The polyvinyl alcohol-based resin composition according to any one of 1 to 5. 7. A hydroxy resin having 10 to 50 parts by weight of a hydrophobic resin (B) and 6 or more carbon atoms with respect to 100 parts by weight of a hydrophilic polyvinyl alcohol resin (A) having a saponification degree of 30 to 90 mol%. Fatty acid or its derivative (C) is 10-60
The polyvinyl alcohol-based resin composition according to any one of claims 1 to 6, wherein the polyvinyl alcohol-based resin composition is blended in an amount by weight. 8. A hydroxy resin having 10 to 50 parts by weight of a hydrophobic resin (B) and 6 or more carbon atoms with respect to 100 parts by weight of a hydrophilic polyvinyl alcohol resin (A) having a saponification degree of 30 to 90 mol%. Fatty acid or its derivative (C) is 10-60
The polyvinyl alcohol-based resin composition according to any one of claims 2 to 6, wherein 10 parts by weight to 10 parts by weight of the plasticizer (D) are mixed. 9. A hot melt adhesive comprising the polyvinyl alcohol-based resin composition according to any one of claims 1 to 8. 10. A paper product using the hot melt adhesive according to claim 9.