JP2007070495A - Solid state adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state adhesive (stick paste) having thinner size than those of conventional ones and having a sufficient strength suitable for its use. <P>SOLUTION: This solid state adhesive comprises a polymer obtained by graft-polymerizing vinylpyrrolidone to a polyvinyl alcohol. It is preferable that the adhesive contains ≥10 wt.% polymer having 12-150 K-value and obtained by graft-polymerizing the vinyl pyrrolidone to the polyvinyl alcohol having 100-4,000 degree of polymerization and 70-100 mol% saponification value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid adhesive (stick paste) mainly used for bonding papers, and more particularly to a solid adhesive formed into a bar having a smaller thickness than conventional ones.

  Various adhesives that are solid at room temperature and mainly used for bonding paper have been proposed so far. As its composition, for example, a composition comprising (1) an adhesive resin, (2) a benzalized sorbit, (3) water and / or an organic solvent is disclosed (Patent Document 1). Moreover, the improvement technique contains (1) adhesive resin, (2) 5-6 sugar alcohol dibenzalides, (3) water and (4) 3-methyl-3-methoxy-1-butanol The thing which consists of an organic solvent to do is disclosed (patent document 2).

  The solid adhesives that have been sold so far have a diameter of 12 mm or more. If such a thick solid adhesive is used, the above-described conventional technique can be used to prevent it from being broken or crushed. Quality products can be manufactured.

However, in recent years, a rod-like solid adhesive having a diameter smaller than 12 mm and 10 mm or less, particularly about 8 mm, has been desired. If it can be formed into such a thin rod shape, it can be stored in a pen-type container or the like in the manner of a pencil lead, and can be made into a small-sized and convenient portable adhesive, which expands the range of use. If the diameter is so thin, the solid adhesive having a sufficient strength could not be obtained by using the above-described conventional technique as it is.
Japanese Patent Publication No. 50-34581 Japanese Patent Publication No.59-25830

  The present invention has been made in view of the above, and an object thereof is to provide a solid adhesive having a thickness smaller than that of a conventional one and having sufficient strength not to be broken or crushed during use. To do.

  As a result of intensive studies, the present inventors have found that a polymer obtained by graft-polymerizing vinyl pyrrolidone to polyvinyl alcohol (hereinafter also simply referred to as a graft polymer) is extremely useful in obtaining the intended solid adhesive, The present invention has been completed.

  That is, the solid adhesive of the present invention contains a polymer obtained by graft polymerization of polyvinyl pyrrolidone to polyvinyl alcohol.

  In the above, 10% by weight or more of a polymer having a K value of 12 to 150 obtained by graft polymerization of vinyl pyrrolidone to polyvinyl alcohol having a polymerization degree of 100 to 4000 and a saponification degree of 70 to 100 mol%. Is preferred.

  As the polymer obtained by graft polymerization of vinyl pyrrolidone to polyvinyl alcohol, a polymer obtained by blending vinyl pyrrolidone in a polyvinyl alcohol solution and polymerizing using hydrogen peroxide or an organic peroxide as an initiator may be used. it can.

  The solid adhesive of the present invention has sufficient strength even when formed into a columnar shape having a diameter of 10 mm or less. Therefore, it is possible to provide a solid adhesive that is easy to carry in a pen shape and that is thin and easy to apply even to fine parts. Furthermore, although the conventional solid adhesive is generally disposable, it is also possible to provide a solid adhesive capable of exchanging the cartridge according to the present invention.

  In the present invention, polyvinyl alcohol (hereinafter also referred to as PVA) as a raw material of the graft polymer used as the adhesive polymer in the present invention has a degree of polymerization of preferably 100 to 4000, and more preferably 100 to 3000. . When the polymerization degree is less than 100, the obtained solid adhesive becomes too soft, and when it exceeds 4000, it becomes hard and brittle.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100 mol%, and more preferably 70 to 99 mol%. If the saponification degree is less than 70 mol%, the solid adhesive becomes too soft, and if it exceeds 99 mol%, it may become hard and brittle.

  Further, even when the K value of the graft polymer is less than 12, the solid adhesive tends to be too soft, and when it exceeds 150, it tends to be hard and brittle.

  The amount of vinylpyrrolidone in the graft polymer is preferably 5 to 900% by weight with respect to polyvinyl alcohol. If it is less than 5% by weight, sufficient adhesiveness cannot be obtained, and if it exceeds 900% by weight, the strength tends to decrease.

  The solid adhesive of the present invention preferably contains 10% by weight or more of the graft polymer. If it is less than 10% by weight, it is difficult to obtain the intended effect of the present invention.

  The graft polymer used in the present invention can be obtained by a production method in which vinyl pyrrolidone is blended in a polyvinyl alcohol solution and polymerized using an appropriate initiator.

  As the initiator, hydrogen peroxide or organic peroxide usually used for radical polymerization can be used. Examples of the organic peroxide include tert-butyl hydroperoxide, di-tert-butyl peroxide, benzoyl peroxide and the like. What is necessary is just to select the reaction method and reaction conditions according to the example of general radical polymerization.

Next, the gelling agent for the solid adhesive of the present invention will be described. The gelling agent is not particularly limited and can be used as long as it is usually used in the production of solid adhesives. Among these, long chain fatty acid salts are preferable from the viewpoint of shape retention, and specifically, laurate, myristate, palmitate, stearate, ricinoleate and the like are preferable. As the alkali for salt formation, Na, K, Ca, Mg, Al, Zn, Ba, NH _{3 and the} like are preferable.

  The gelling agent and the graft polymer are dissolved in an aqueous solvent and filled in a solid adhesive container. Water is preferable as the aqueous solvent, but the aqueous solvent may contain alcohols such as ethanol and isopropyl alcohol; ketones such as methyl ethyl ketone; esters such as ethyl acetate.

  A polyhydric alcohol can also be blended in order to act as a solubilizing agent for dissolving the gelling agent in the aqueous solvent and as a wetting agent and a plasticizer. Examples include dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and tetramethylene glycol; and trihydric or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol. Further, ketose (hexulose, heptulose, etc.), aldonic acid, aldaric acid, deoxy sugar, inositol sugar cyclic alcohol and the like can also be used.

  As described above, the solid adhesive of the present invention can be formed from a gelling agent, an adhesive polymer, and water, but the preferred blending amount at this time is gelling agent: 5 to 10 parts by mass, Adhesive polymer: 25-50 parts by mass, water: 20-60 parts by mass, polyhydric alcohol: 10-20 parts by mass.

  Other known additives may be added to the solid adhesive of the present invention. Examples of such additives include polyalkylene glycol, polyalkylene oxide, polyvinyl alcohol, polyacrylic acid, polyalkyleneimine, polyalkyloxazoline, water-soluble polyurethane resin, water-soluble nylon resin, and partial hydrolysis of polyvinyl acetate. , Alkyl vinyl ether and maleic anhydride copolymer, water-soluble polymers such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, water-soluble starch, gelatin, pectin, gum arabic and guar gum; adhesive resins such as phenol resins and alkyd resins Oils and fats such as linseed oil, lysine, castor oil, soybean oil, palm oil, tall oil, fish oil, oleic acid, linoleic acid, linolenic acid; polyoxyalkylene ether, polyoxyalkylene fatty acid ester, poly Surfactants such as xyalkylene sorbitan (mono, di, tri) fatty acid ester, (poly) glycerin (mono, di, tri) fatty acid ester, sorbitan (mono, di, tri) stearate, etc .; lubricants such as liquid paraffin Shape retention agents such as benzalized sorbit; inorganic extenders such as silica, alumina, titanium dioxide, barium oxide, and zinc oxide; dextrins such as dextrin and cyclodextrin, and the like, and an appropriate amount may be used as necessary. Moreover, a fragrance | flavor, a fluorescent whitening agent, an antibacterial agent, antiseptic | preservative, a coloring agent, etc. can be mix | blended.

  The specific production method of the solid adhesive is not particularly limited, and a conventionally used method is used. After mixing a polyhydric alcohol as a dissolution aid in an aqueous solvent (preferably water), this mixture is used. Add a long-chain fatty acid salt as a gelling agent while heating and dissolve uniformly, and further dissolve the adhesive polymer, and if necessary, add the above additives to obtain a viscous What is necessary is just to fill a liquid substance (for example, lipstick shape etc.) and to solidify by cooling. The dissolution order of the gelling agent, the adhesive polymer, and the additive is not particularly limited.

  The solid adhesive of the present invention is preferably formed into a cylindrical shape having a diameter of 10 mm or less. However, the present invention is not limited to this, and can be appropriately changed within the scope of the object of the present invention. The cross-sectional shape may be, for example, an ellipse or other shapes.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

[Examples 1 to 4, Comparative Examples 1 and 2]
47 parts of water and 14 parts of glycerin were charged into a reaction vessel, heated to 90 ° C. while stirring, 7 parts of sodium stearate was added, and the mixture was stirred for about 1 hour to dissolve. Next, 32 parts of the following powdery polymers 1 to 6 were added little by little so as not to become mamaco to obtain a viscous white mixture. The molten composition was poured into a mold in which a part to be joined with the holder was previously inserted, and cooled to solidify. It was taken out from the mold, cut into a predetermined length (diameter 8 mm, length 52 mm), and stored in a sealed cartridge case.

  The bending strength of the solid adhesive of the present invention thus obtained was measured by the bending strength test of 6.5 of JIS-6026, and the crushing strength was measured with a sample of about 25 ° C. on a flat table. The disk-shaped loading tip having a diameter of 12 mm was lowered at a speed of about 4 mm / second and obtained as a burden when the sample started to collapse. The results are shown in Table 1.

Also, place the sample in a polypropylene refill case, store it in a thermostatic bath at 50 ° C for 24 hours, remove it, cool it to room temperature, and then test whether the stick can be removed from the refill case. It was evaluated with. The results are also shown in Table 1.
○: Can be taken out without problems, ×: Collapsed when taken out

Powdery polymer 1: Polyvinyl alcohol (PVA) (polymerization degree 200, saponification degree 98-99 mol%) was graft-polymerized with vinylpyrrolidone (VP) (vs. PVA 5.26 wt%), K value 23, solid content 97 .1% powder.
Powdery polymer 2: A powder having a K value of 31 and a solid content of 98.5% obtained by graft polymerization of PVA (polymerization degree 2400, saponification degree 98-99 mol%) with VP (vs. PVA 42.9 wt%).
Powdered polymer 3: Powder having a K value of 40 and a solid content of 96.3% obtained by graft polymerization of PVA (polymerization degree 500, saponification degree 72.5-74.5 mol%) with VP (vs. PVA 150 wt%).
Powdered polymer 4: Powder having a K value of 94 and a solid content of 99.0% obtained by graft polymerization of PVA (polymerization degree: 3500, saponification degree: 87-89 mol%) with VP (vs. PVA 900 wt%).
Powdered polymer 5: Powder of polyvinyl alcohol (polymerization degree 3500, saponification degree 87-89 mol%).
Powdery polymer 6: Polyvinylpyrrolidone K-30 powder.

  The solid adhesive of the present invention is mainly used for bonding paper.

Claims (3)

  A solid adhesive comprising a polymer obtained by graft polymerization of vinyl pyrrolidone to polyvinyl alcohol.   It is characterized by containing 10% by weight or more of a polymer having a K value of 12 to 150 obtained by graft polymerization of vinyl pyrrolidone to polyvinyl alcohol having a polymerization degree of 100 to 4000 and a saponification degree of 70 to 100 mol%. The solid adhesive according to claim 1. The polymer obtained by graft polymerization of vinyl pyrrolidone to polyvinyl alcohol is obtained by blending vinyl pyrrolidone in a polyvinyl alcohol solution and polymerizing using hydrogen peroxide or an organic peroxide as an initiator. The solid adhesive according to claim 1 or 2.