JP2009052008A - Adhesive and laminate comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive having good adhesiveness between a polylactic acid-based resin material and a different resin material. <P>SOLUTION: An adhesives for a polylactic acid-based resin material which comprises a polyether type polyurethane resin (A) is provided. The adhesive comprising (A) and a polylactic acid-based resin (B) is provided, wherein the mass ratio (A/B) is 99/1-40/60. The polylactic acid resin-based adhesive comprising (A) and a terpene-based tackifier (C) is provided, wherein the mass ratio (A/C) is 100/1-100/40. The polylactic acid resin-based adhesive comprising (A), (B) and (C) is provided, wherein the mass ratio (A/B) is 99/1-40/60 and the mass ratio [(A+B)/C] is 100/1-100/40. Also provided is the polylactic acid-based adhesives which further contains a wax (D). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adhesive containing a polyether type polyurethane resin, and particularly relates to an adhesive excellent in adhesiveness between a polylactic acid resin material and a different resin material, and a laminate and a laminate using the adhesive. It is.

In recent years, due to environmental considerations, attention has been focused on plant-derived resins that do not rely on petroleum raw materials and have a low environmental impact during disposal. Among them, polylactic acid resins made from corn, sweet potatoes and other agricultural crops are advantageous in terms of resources, are biodegradable, and have excellent transparency, hot melt moldability, and heat resistance. Has reached.
For example, a molded body such as a film using a polylactic acid-based resin has been put into practical use, but there is room for improvement in mechanical properties, barrier properties, etc. in use. As one of means for solving these problems, compounding with different resin materials can be mentioned. For example, it is considered that a weak point of a polylactic acid resin film can be compensated by laminating a different resin film such as a polyolefin film having excellent barrier properties and flexibility on the polylactic acid resin film.

When the polylactic acid resin film and the different resin film are bonded and laminated, it is preferable to use an adhesive containing a plant-derived material as the adhesive. Water-based adhesives are attracting attention as environmentally friendly adhesives.
In other words, the adhesive containing the medium has a solvent property and an aqueous property. However, since the solvent adhesive contains an organic solvent, there is a risk of ignition, and there are problems such as environmental pollution. In recent years, regulations on volatile organic compounds (VOC) have become particularly strict, and the aspect of adhesives is shifting to water-based adhesives. Among them, the aqueous dispersion (emulsion) has the advantage that the current coating line can be used almost as it is because it has a low environmental impact and is liquid like a solvent-based adhesive. Is the most promising.

However, it is difficult to laminate the polylactic acid resin material and the different resin material to make up for the weak points of the polylactic acid resin molding because the adhesive used has insufficient adhesiveness.
For example, studies on a resin composition composed of a polylactic acid resin and a urethane resin (Patent Documents 1 and 2) have been conducted, but for the purpose of imparting impact strength, mechanical strength, and melt tension to the polylactic acid resin. Thus, no investigation has been made on adhesives, particularly water-based adhesives. In addition, there is a document that mentions a coating agent composed of an aqueous dispersion of a polylactic acid resin and a petroleum resin emulsion (Patent Document 3), but since this is a study on a polishing agent for floors, it is studied as an adhesive. Not. A water-based adhesive comprising a polylactic acid resin and a polyester-based resin has been studied for use as an aqueous adhesive (Patent Document 4). However, the polylactic acid resin film and paper can be bonded to each other substantially. However, there is room for study on adhesion between the polylactic acid resin substrate and the different resin substrate. In addition, the present inventors have also studied the use of an aqueous dispersion of a biodegradable polyester resin containing a lactic acid residue as an adhesive (Patent Document 5), but bothers to polymerize a resin having a specific composition. In addition, there is room for study on the adhesion between the polylactic acid resin substrate and the different resin substrate. Patent Document 5 mentions the possibility of adding a urethane resin, but there is room for study to improve the adhesion between a polylactic acid resin substrate and a different resin substrate.
JP 2005-320409 A JP 2002-037995 A JP 2005-002303 A JP 2003-128888 A JP 2004-300284 A

  An object of the present invention is to provide an adhesive that solves the above-described problems and has good adhesion between a polylactic acid resin material and a different resin material.

As a result of intensive studies, the present inventors have found that an adhesive containing a specific urethane resin exhibits good adhesion (laminate strength) between a polylactic acid resin material and a different resin material, It has been found that laminating strength is increased when a polylactic acid resin which hardly exhibits an adhesive effect by itself is contained in the adhesive, and the present invention has been achieved.
That is, the gist of the present invention is as follows.
(1) An adhesive for a polylactic acid-based resin material, comprising a polyether type polyurethane resin (A).
(2) The polyether type polyurethane resin (A) and the polylactic acid resin (B) are contained, and the mass ratio (A / B) of (A) and (B) is 99/1 to 40/60. A polylactic acid resin-based adhesive.
(3) It contains a polyether type polyurethane resin (A) and a terpene tackifier (C), and the mass ratio (A / C) of (A) to (C) is 100/1 to 100/40. A polylactic acid resin adhesive characterized by being.
(4) A polyether type polyurethane resin (A), a polylactic acid resin (B), and a terpene tackifier (C), and a mass ratio (A / B) of (A) and (B) Is 99/1 to 40/60, and the mass ratio ((A + B) / C) of (A), (B), and (C) is 100/1 to 100/40. Polylactic acid resin adhesive.
(5) The adhesive according to any one of (1) to (4), which contains a wax (D).
(6) The adhesive according to any one of (1) to (5), which contains a medium (E).
(7) An adhesive layer comprising the adhesive according to any one of (1) to (6) formed on a substrate.
(8) A laminate comprising a substrate and the adhesive layer according to (7).
(9) A laminate comprising a base material, the adhesive layer according to (7), and an adherend laminated on the adhesive layer.
(10) The laminate according to (8), wherein the substrate is a polylactic acid resin material or a polyolefin resin material.
(11) The laminate according to (9), wherein the substrate and / or adherend is a polylactic acid resin material and / or a polyolefin resin material.
(12) Polyether type polyurethane resin (A) aqueous dispersion and polylactic acid resin (B) aqueous dispersion and / or terpene tackifier (C) aqueous dispersion and / or wax (D) aqueous dispersion And the method for producing an adhesive according to (6).

  The adhesive of the present invention can satisfactorily bond (laminate) a polylactic acid resin material and a different resin material, particularly a polyolefin resin film. Moreover, the laminate strength can be improved by including a polylactic acid resin in the adhesive component. Furthermore, by replacing a part of the adhesive with a plant-derived polylactic acid resin, it is possible to provide a highly preferable adhesive for the environment.

Hereinafter, the present invention will be described in detail.
The adhesive of the present invention needs to contain a polyether type polyurethane resin (A). When a polyurethane resin other than the polyether-type polyurethane resin, for example, a polyester-type polyurethane resin or a polycarbonate-type polyurethane resin is used, the polylactic acid resin and the dissimilar resin material cannot be favorably bonded.
The polyurethane resin is a polymer containing a urethane bond in the main chain, and the polyether type polyurethane resin (A) is obtained, for example, by a reaction between a polyether polyol compound and a polyisocyanate compound.

As the polyether polyol compound constituting the polyether type polyurethane resin (A), polyoxyethylene polyol (polyethylene glycol and the like), polyoxypropylene polyol (polypropylene glycol and the like), polyoxybutylene polyol (polytetramethylene glycol and the like), Examples thereof include copolymerized polyether polyols (polyoxyethylene glycol and polyoxypropylene glycol block copolymers, random copolymers, etc.). Among them, polytetramethylene glycol is preferred for the purpose of improving adhesiveness.
As other polyols, 1,3-butanediol, 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, as long as the effects of the present invention are not impaired. Neopentyl glycol, 1,4-cyclohexanedimethanol, methyl-1,5-pentanediol, 1,8-octanediol, 2-ethyl-1,3-hexanediol and the like may be used in combination.

Moreover, as a polyisocyanate compound which comprises a polyether type polyurethane resin (A), the 1 type, or 2 or more types of mixture of aromatic, aliphatic, and alicyclic well-known diisocyanates can be used.
Specific examples of diisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dimethyl diisocyanate, lysine diisocyanate. , Hydrogenated 4,4'-diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, dimerized isocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group, and adducts, biurets, isocyanurates, etc. Diisocyanate is preferred.

The weight average molecular weight of the polyether type polyurethane resin (A) is preferably in the range of 10,000 to 5,000,000, more preferably in the range of 20,000 to 3,000,000, and in the range of 30,000 to 1,000,000. More preferably. If the weight average molecular weight is less than 10,000, the adhesiveness may not be exhibited, and if the weight average molecular weight exceeds 5 million, the adhesiveness may be lowered.
The weight average molecular weight of the polyether type polyurethane resin (A) can be analyzed by GPC analysis (manufactured by Shimadzu Corporation, solvent: tetrahydrofuran, refractive index spectrometer, polystyrene conversion) and the like.

  The adhesive of the present invention preferably contains a polylactic acid resin (B) in addition to the polyether type polyurethane resin (A). The mass ratio (A / B) is preferably 99/1 to 40/60, more preferably 99/1 to 50/50, and still more preferably 95/5 to 50/50. . When the proportion of the polylactic acid resin (B) is less than 1% by mass, the effect of improving the adhesiveness is small, and when the proportion of the polylactic acid resin (B) exceeds 60% by mass, the effect of improving the adhesiveness is remarkably reduced. To do.

  In the present invention, the polylactic acid resin (B) is a resin polymerized using lactic acid as a raw material. Specific examples of the lactic acid include L-lactic acid, D-lactic acid, DL-lactic acid, a mixture thereof, and lactide of a cyclic dimer of lactic acid. Moreover, you may use together hydroxycarboxylic acid as a raw material of a polylactic acid-type resin (B). Specific examples of hydroxycarboxylic acids include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, and 6-hydroxycarboxylic acid. Furthermore, cyclic ester intermediates of hydroxycarboxylic acid, for example, glycolide which is a dimer of glycolic acid and ε-caprolactone which is a cyclic ester of 6-hydroxycaproic acid can be mentioned.

  The production method of the polylactic acid resin (B) is not particularly limited. For example, in the case of polylactic acid, a method of directly dehydrating polycondensation of L-lactic acid, D-lactic acid, and DL-lactic acid, or a cyclic dimer of lactic acid. And a method of ring-opening polymerization of lactide. Instead of these, a commercially available polylactic acid resin may be used.

The adhesive of the present invention preferably contains a terpene tackifier (C) in addition to the polyether type polyurethane resin (A). The mass ratio (A / C) is preferably 100/1 to 100/40, more preferably 100/10 to 100/35, and still more preferably 100/20 to 100/30. . When the terpene tackifier (C) is less than 1 part by mass with respect to 100 parts by mass of the polyether type polyurethane resin (A), the effect of improving the adhesiveness is small, and the terpene tackifier (C) When it exceeds 40 mass parts, the adhesive improvement effect will fall remarkably.
Examples of the terpene tackifier (C) include a low polymerization terpene system, an α-pinene polymer, a β-pinene polymer, a terpene phenol system, an aromatic modified terpene system, and a hydrogenated terpene.

  Furthermore, the adhesive of the present invention preferably contains three components of a polyether type polyurethane resin (A), a polylactic acid resin (B), and a terpene tackifier (C). The mass ratio (A / B) of (A) and (B) is 99/1 to 40/60, and the mass ratio of (A), (B) and (C) ((A + B) / C ) Is preferably 100/1 to 100/40, the mass ratio (A / B) is 95/5 to 50/50, and the mass ratio ((A + B) / C) is 100/20. It is preferably ~ 100/30.

Furthermore, it is preferable to mix | blend wax (D) with the adhesive agent of this invention. Thereby, adhesiveness improves and also blocking resistance can be provided. The blending amount of the wax (D) is 100 parts by mass of the polyether type polyurethane resin (A) or the polyether type polyurethane resin (A) and the polylactic acid resin (B) and / or the terpene type tackifier (C). On the other hand, it is preferable that it is the range of 1-200 mass parts, and it is more preferable that it is the range of 10-100 mass parts. If the blending amount is less than 1 part by mass, the blending effect is small, and even if blending exceeds 200 parts by mass, it is difficult to expect further improvement of the effect. In some cases, pot life and adhesiveness are lowered.
The wax (D) may be a synthetic wax or a natural wax, but a natural wax is preferred from the viewpoint of environmental problems. Specifically, plant waxes such as candelilla wax, carnauba wax, rice wax, and wax, animal waxes such as shellac wax and lanolin wax, mineral waxes such as montan wax and ozokerite, petroleum oils such as paraffin wax and microcrystalline wax A wax is mentioned. Furthermore, what has passed FDA (Food and Drug Administration) from a viewpoint of safety | security is preferable. Specific examples include candelilla wax, carnauba wax, rice wax, and wood wax. These waxes may be used alone or in combination of two or more.

As described above, the adhesive of the present invention contains a polyether type polyurethane resin (A), preferably a polylactic acid resin (B) and / or a terpene tackifier (C) and / or a wax (D ). Adhesives of these constructions are laminates consisting of a substrate / adhesive layer by melting and extruding onto a substrate using a known method or by co-extrusion with a melt of a substrate material. The body can be manufactured. Also, by co-extrusion of the adhesive melt and the adherend melt onto the substrate, or the base material melt, the adhesive melt, and the adherend material melt. By co-extrusion, a laminate comprising a substrate / adhesive layer / adhered body can be produced. For example, when a polylactic acid resin material is used as a substrate and a different resin material is used as an adherend, These can be bonded and laminated.
The extrusion temperature needs to be equal to or higher than the melting point or flow start temperature of the resin, the base material, and the adherend material constituting the adhesive, and is preferably higher by 10 ° C. than the melting point or flow start temperature. For example, in the case of an adhesive comprising a polyether type polyurethane resin (A), a polylactic acid resin (B), and a terpene tackifier (C), the extrusion temperature is preferably 180 to 230 ° C, and 190 to 220 ° C. Further preferred. If the temperature is too low, the extrusion becomes unstable or is likely to be overloaded. Conversely, if the temperature is too high, the resin decomposes and the strength of the resulting laminate is reduced or coloring occurs. Therefore, it is not preferable.

  Furthermore, the adhesive of the present invention may contain a medium (E), and by including the medium (E) in the adhesive, the adhesive can be used by applying a coating method.

In the present invention, the medium (E) includes an organic solvent, water, or a mixture of water and a hydrophilic organic solvent, and is preferably a liquid that is liquid at room temperature and normal pressure and can be volatilized and removed by heating or reduced pressure. .
Examples of organic solvents include diethyl ketone (3-pentanone), methyl propyl ketone (2-pentanone), methyl isobutyl ketone (4-methyl-2-pentanone), 2-hexanone, 5-methyl-2-hexanone, 2 -Ketones such as heptanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone, aromatic hydrocarbons such as toluene, xylene, benzene, Solvesso 100, Solvesso 150, butane, pentane, hexane, cyclohexane , Aliphatic hydrocarbons such as heptane, octane and nonane, methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, o-dichlorobenzene, m-di Halogen-containing compounds such as chlorobenzene and p-dichlorobenzene, Esters such as ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, diethyl carbonate, γ-butyrolactone, isophorone, etc. And a hydrophilic organic solvent described later. By incorporating these organic solvents into the adhesive as a medium (E), a solvent-based adhesive can be obtained. The production method is not particularly limited, and a commercially available polyether type polyurethane resin (A) and, if necessary, a polylactic acid resin (B) and / or a terpene tackifier (C) and / or a wax ( D) may be simultaneously dissolved in an organic solvent, or those separately dissolved in an organic solvent may be mixed at a specific ratio.

In the present invention, the medium (E) includes water or water and hydrophilicity from the standpoints of storage stability, ease of handling, and environmental protection, resource saving, regulation of dangerous goods according to the Fire Service Act, workplace environment improvement, and the like. Preference is given to using a mixture of organic solvents. By containing these in the adhesive, an aqueous adhesive can be obtained.
When a mixture of water and a hydrophilic organic solvent is used as the medium (E), the hydrophilic organic solvent is added mainly for imparting wettability to the substrate. The ratio of the hydrophilic organic solvent in the medium (E) is preferably 20% by mass or less, more preferably 10% by mass or less, more preferably 5% by mass or less from the viewpoints of the environment and the liquid stability of the aqueous adhesive. % Or less is more preferable, and it is particularly preferable not to contain it.

  Examples of hydrophilic organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl. Alcohols such as alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone and isophorone, tetrahydrofuran (hereinafter , Abbreviated as THF), ethers such as dioxane, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, acetic acid-3 Esters such as methoxybutyl, methyl propionate, ethyl propionate, diethyl carbonate, dimethyl carbonate, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether Glycols such as acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate Conductor, and further, 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, and the like. Among the above hydrophilic organic solvents, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, THF, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether are easy to handle. Particularly preferred are ethanol, n-propanol, and isopropanol. These hydrophilic organic solvents may be used as a mixture of two or more.

  The method for producing the aqueous adhesive comprising the polyether type polyurethane resin (A) and the medium (E) is not particularly limited, and a commercially available polyurethane resin aqueous dispersion may be used. Examples of commercially available aqueous dispersants include NeoRez series manufactured by Enomoto Kasei Co., Ltd., Adeka Bon titer series manufactured by Adeka Co., Ltd., and Takelac series manufactured by Mitsui Chemicals.

  The method for producing an aqueous adhesive comprising the polyether type polyurethane resin (A), the polylactic acid resin (B), and the medium (E) is not particularly limited. The polyether type polyurethane resin (A) and the polylactic acid resin (B) may be dispersed in water simultaneously or continuously, but the simplest method is the above polyether type polyurethane resin (A) aqueous dispersion, A method of mixing the following polylactic acid-based resin (B) aqueous dispersion at a specific ratio is exemplified.

  Moreover, the manufacturing method of the water-based adhesive which consists of a polyether type polyurethane resin (A), a terpene type tackifier (C), and a medium (E) is not specifically limited. The polyether type polyurethane resin (A) and the terpene-based tackifier (C) may be dispersed in water simultaneously or continuously, but the simplest method is that the above polyether type polyurethane resin (A) aqueous dispersion and And a method of mixing the following terpene tackifier (C) with an aqueous dispersion at a specific ratio.

  Moreover, the manufacturing method of the water-based adhesive which consists of a polyether type polyurethane resin (A), a wax (D), and a medium (E) is not specifically limited. The polyether type polyurethane resin (A) and the wax (D) may be dispersed in water simultaneously or continuously. The simplest method is to use the polyether type polyurethane resin (A) aqueous dispersion and the following wax ( D) A method of mixing the aqueous dispersion at a specific ratio can be mentioned.

  Furthermore, the method for producing an aqueous adhesive comprising the polyether type polyurethane resin (A), the polylactic acid resin (B), the terpene tackifier (C), and the medium (E) is not particularly limited. The polyether type polyurethane resin (A), the polylactic acid resin (B), and the terpene tackifier (C) may be dispersed in water simultaneously or continuously, but the simplest method is the polyether type polyurethane resin ( A) An aqueous dispersion, the following polylactic acid resin (B) aqueous dispersion and the following terpene tackifier (C) aqueous dispersion are mixed at a specific ratio.

  Furthermore, the manufacturing method of the aqueous adhesive which consists of a polyether type polyurethane resin (A), a polylactic acid-type resin (B), a wax (D), and a medium (E) is not specifically limited. The polyether type polyurethane resin (A), the polylactic acid resin (B) and the wax (D) may be dispersed in water simultaneously or continuously, but the simplest method is the polyether type polyurethane resin (A) aqueous dispersion. And the following polylactic acid-based resin (B) aqueous dispersion and the following wax (D) aqueous dispersion are mixed at a specific ratio.

  Furthermore, the manufacturing method of the water-based adhesive which consists of polyether type polyurethane resin (A), terpene-type tackifier (C), wax (D), and medium (E) is not specifically limited. The polyether-type polyurethane resin (A), the terpene-based tackifier (C), and the wax (D) may be dispersed in water simultaneously or continuously, but the simplest method is the polyether-type polyurethane resin (A) aqueous A method of mixing the dispersion, the following terpene-based tackifier (C) aqueous dispersion, and the following wax (D) aqueous dispersion in a specific ratio can be mentioned.

  Further, the method for producing an aqueous adhesive comprising the polyether type polyurethane resin (A), the polylactic acid resin (B), the terpene tackifier (C), the wax (D) and the medium (E) is not particularly limited. . The polyether type polyurethane resin (A), polylactic acid resin (B), terpene tackifier (C) and wax (D) may be dispersed in water simultaneously or continuously. A method of mixing an ether type polyurethane resin (A) aqueous dispersion, the following polylactic acid resin (B) aqueous dispersion, the following terpene tackifier (C) and the following wax (D) aqueous dispersion in a specific ratio. Is mentioned.

The production method of the polylactic acid resin (B) aqueous dispersion is not particularly limited, and examples thereof include a phase inversion emulsification method and a forced emulsification method. For example, the method described in JP-A-2005-008733, that is, a raw material such as polylactic acid resin (B), water, a basic compound, a hydrophilic organic solvent is charged into a sealable container, and then a tank Polylactic acid by maintaining stirring at 45 to 200 ° C., preferably 60 to 150 ° C., more preferably 80 to 120 ° C., and preferably stirring until coarse particles disappear (for example, 5 to 120 minutes). The dispersion can be obtained by sufficiently dispersing the system resin (B) and then cooling to 40 ° C. or lower, preferably with stirring. At this time, when the temperature in the tank is lower than 45 ° C., it becomes difficult to disperse the polylactic acid resin (B). A reaction in which the temperature in the tank exceeds 200 ° C. is not preferable because it is not economical and the hydrolysis reaction of the polylactic acid resin (B) may proceed remarkably. Thereafter, the hydrophilic organic solvent is distilled off to obtain a polylactic acid resin (B) aqueous dispersion.
The polylactic acid resin (B) aqueous dispersion can be produced by the above method, but a commercially available polylactic acid resin aqueous dispersion may be used. Examples of commercially available aqueous dispersants include the Prasema series manufactured by Daiichi Kogyo Seiyaku and the Randy PL series manufactured by Miyoshi Oil & Fats.

The production method of the terpene tackifier (C) aqueous dispersion is not particularly limited, and examples thereof include a phase inversion emulsification method and a forced emulsification method.
Commercially available terpene tackifier aqueous dispersions may also be used. Examples of commercially available aqueous dispersants include the Nanolet series manufactured by Yashara Chemical Co., the Resem series manufactured by Chukyo Yushi Co., Ltd., and the Tamanol series manufactured by Arakawa Chemical Co., Ltd.

The method for producing the aqueous wax (D) dispersion is not particularly limited, and examples thereof include a phase inversion emulsification method and a forced emulsification method.
A commercially available aqueous wax dispersion may also be used. Examples of the commercially available aqueous dispersant include a wax emulsion manufactured by Unitika and an EMUSTAR series manufactured by Nippon Seiki.

  In the adhesive containing the medium (E) of the present invention, the total mass of the polyether type polyurethane resin (A), the polylactic acid resin (B), the terpene tackifier (C), and the wax (D) (that is, (A) or [(A) + (B)] or [(A) + (C)] or [(A) + (D)] or [(A) + (B) + (C)] or [( A) + (B) + (D)] or [(A) + (C) + (D)] or [(A) + (B) + (C) + (D)], hereinafter solid content Concentration) (solid content concentration) is appropriately adjusted depending on the type of the medium (E), the lamination conditions, the thickness and performance of the target adhesive layer, and is not particularly limited. 1 to 60% by mass is preferable, and 10 to 50% by mass is more preferable in terms of maintaining an appropriate amount and expressing good adhesive layer forming ability. , Particularly preferably 20 to 40 wt%. If it is less than 1% by mass, sufficient adhesiveness is difficult to obtain, and if it exceeds 60% by mass, storage stability may be lowered or handling may be difficult.

  The adhesive of the present invention may contain a surfactant, but the smaller the content, the better the adhesion and adhesion between the adhesive layer and the substrate, and the adhesive changes with time after long-term storage. It is small and does not cause sanitary problems. Accordingly, the surfactant component is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, with respect to 100 parts by mass of the solid content. Most preferably it is not contained.

In order to further improve the adhesiveness, 0.1 to 50 parts by mass, preferably 0.5 to 30 parts by mass of a crosslinking agent is added to the adhesive of the present invention with respect to 100 parts by mass of the solid content. it can. When the addition amount of the crosslinking agent is less than 0.1 parts by mass, the degree of improvement of the coating film performance is small, and when it exceeds 50 parts by mass, the liquid stability of the adhesive containing the medium (E), the adhesive layer Performance such as adhesiveness and workability may be reduced.
As the crosslinking agent, a crosslinking agent having self-crosslinking property, a compound having a plurality of functional groups that react with a carboxyl group in the molecule, and a metal complex having a polyvalent coordination site can be used. Of these, isocyanate compounds , Melamine compound, urea compound, epoxy compound, carbodiimide compound, oxazoline group-containing compound, aziridine compound, zirconium salt compound, silane coupling agent, compound having two or more (meth) acrylic groups in the molecule, A compound having one (meth) acrylic group and one glycidyl group is preferred. Moreover, you may use combining these crosslinking agents.

Moreover, in order to improve adhesiveness, you may mix | blend a plasticizer with the adhesive agent of this invention. The blending ratio of the plasticizer is preferably in the range of 0.1 to 30% by mass and more preferably in the range of 0.1 to 20% by mass with respect to the polylactic acid resin (B). When the addition amount is less than 0.1% by mass, the effect of addition is small, and even if the addition amount exceeds 30% by mass, it is difficult to expect further improvement of the effect, and in some cases, the adhesiveness is lowered.
The plasticizer is compatible with the polylactic acid resin (B), is non-volatile, is non-toxic from the viewpoint of environmental problems, and has passed FDA (Food and Drug Administration). Is preferred. Specifically, ether ester plasticizers and oxyacid ester plasticizers. Specific examples of the ether ester plasticizer include bismethyldiethylene glycol adipate and bisbutyldiethylene glycol adipate. Specific examples of the oxyester plasticizer include tributyl acetyl citrate. These plasticizers may be used alone or in combination of two or more.

To the adhesive of the present invention, other polymers, other tackifier components, and the like can be further added.
Examples of other polymers include polyester resins, polyolefin resins, acrylic resins, modified nylon resins, silicone resins, and epoxy resins. You may use these in mixture of 2 or more types.
Examples of the tackifier component include rosins, petroleum resins, coumarone resins, and indene resins. Examples of rosins include polymerized rosin, disproportionated rosin, maleated rosin, fumarated rosin, and glycerin ester, pentaerythritol ester, methyl ester, ethyl ester, butyl ester, ethylene glycol ester, diethylene glycol ester, triethylene glycol. Examples include esters. As petroleum resins, petroleum resins obtained by polymerizing petroleum fractions having 5 carbon atoms, petroleum resins obtained by polymerizing petroleum fractions having 9 carbon atoms, and petroleum resins obtained by hydrogenation of these, maleic acid-modified, phthalic acid-modified petroleum Resin etc. are mentioned.

  Furthermore, the adhesive of the present invention includes various agents such as a leveling agent, an antifoaming agent, an anti-waxing agent, a pigment dispersant, a pigment, a lubricant, an ultraviolet absorber, and an antistatic agent, as long as the effects of the present invention are not impaired. May be added.

  Since the adhesive containing the medium (E) of the present invention is excellent in film forming ability, known film forming methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain Uniformly coat the surface of various substrates by flow coating, spray coating, dip coating, brushing, etc., set as near room temperature as necessary, and then heat treatment for drying or drying and baking By removing, a laminate in which an adhesive layer composed of a uniform resin coating film is formed on the surfaces of various substrates can be obtained. As a heating device at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. Further, the heating temperature and the heating time are appropriately selected depending on the type of the medium (E), the characteristics of the base material, the type and blending amount of the curing agent, and are not particularly limited. For example, the heating temperature 50 to 300 Can be used in the range of about ℃.

  In the present invention, the thickness of the adhesive layer formed on the substrate is not particularly limited, but is preferably 0.05 to 200 μm, more preferably 0.1 to 150 μm, and 0.5 to 100 μm. More preferably. If the thickness is less than 0.05 μm, the adhesiveness is low, and if it exceeds 200 μm, a long drying time is required when an adhesive containing the medium (E) is used.

  Examples of the substrate for forming the adhesive layer made of the adhesive of the present invention include paper, synthetic paper, various thermoplastic resin molded articles, glass, metal, aluminum foil, plastic, and the like. The adhesive of the present invention is a resin. Since a polylactic acid resin (B) can also be used as a component, it is preferably a plant-derived material, such as paper, a polylactic acid resin material or chitosan of a natural polysaccharide, and particularly a polylactic acid resin material. preferable. Moreover, the adherend mentioned later can also be used as a base material.

  Among the above-mentioned base materials, examples of the thermoplastic resin molded body include a molded body molded by an injection molding method, a blow molding method, an extrusion molding method, an extrusion foam molding method, and the like. Can be mentioned. The thickness of the film is not particularly limited, but is usually 0.5 to 1000 μm, preferably 1 to 500 μm, more preferably 1 to 100 μm, and particularly preferably 1 to 50 μm. The film is preferably subjected to a physical surface treatment such as a corona treatment, but the adhesive of the present invention is excellent in wettability and may not be applied. Moreover, when the shape of a base material is a foam sheet, the thickness is 0.1-5 mm normally, it is preferable that it is 0.5-4 mm, and it is more preferable that it is 1-3 mm.

By laminating the adherend on the adhesive layer formed on the base material, a laminate composed of the base material / adhesive layer / adherence body can be obtained.
The conditions for laminating the adherend are not particularly limited, but when the temperature is 40 ° C. or higher and the substrate is a resin material, it is preferably below the melting point of the resin. As a method of laminating the adherend, for example, a method of laminating an adherend film on an adhesive layer on a substrate while applying pressure with a hot roll, or a molten adherend material on a substrate. A method of extrusion laminating on the adhesive layer is mentioned.

  As the adherend, the above-mentioned base material can be used. However, in order to make use of the characteristics of the adhesive of the present invention, the combination of the base material and the adherend is made of a polylactic acid resin material and other materials. A combination of materials is preferable, and as the adherend to be laminated with the polylactic acid resin material, a thermoplastic resin material is particularly preferable. Specific examples of the adherend include polyolefin resin materials such as polyethylene, polypropylene, ionomer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and cyclic polyolefin resin materials, nylon 6, nylon 66, nylon 46, and the like. Polyamide resin materials, polyethylene terephthalate (hereinafter referred to as PET), amorphous PET (A-PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, and other polyester resin materials, Examples include polystyrene resin materials, polyimide resin materials, polycarbonate resin materials, polyarylate resin materials, or mixtures thereof. Adhesive properties of the adhesive of the present invention and polylactic acid resin materials From the viewpoint of imparting barrier properties such as, it is preferable to use a polyolefin resin material as the adherend.

  By using the adhesive of the present invention, the laminate strength of the laminate can be 1.0 N / 15 mm or more, preferably 1.5 N / 15 mm or more, more preferably 2.0 N / 15 mm or more. If the laminate strength is less than 1.0 N / 15 mm, it may be peeled off during handling.

  By applying thermoforming to a laminate or a laminate obtained using the adhesive of the present invention, it can be formed into a shape such as a saddle shape, a box shape, or a bottle shape. These molded bodies can be used for applications such as containers and trays.

Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to these.
(A) Evaluation method (1) Structure of urethane resin It determined by infrared spectroscopic analysis and ¹ H-NMR analysis. When the medium (E) was included, the measurement was performed after removing the medium (E) in the same manner as the method for obtaining the solid content concentration described below.
Infrared spectroscopic analysis: Determined by the KBr method using Perkin Elmer System 2000.
¹ H-NMR analysis: It was obtained using JEOL Ltd. Lambda 300 MHz NMR. DMSO (d ₃ ) was used as a solvent, and measurement was performed at 80 ° C.
(2) Solid Concentration of Aqueous Adhesive An appropriate amount of the adhesive was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to determine the solid content concentration.
(3) Pot life of aqueous adhesive The appearance of the aqueous dispersion after leaving the aqueous adhesive at room temperature for 30 days was evaluated in the following three stages.
○: No change in appearance.
Δ: Thickening and slight precipitation are observed.
X: Solidification, agglomeration, and significant precipitation are observed.
(4) Adhesiveness After affixing an adhesive tape (TF-12 manufactured by Nichiban Co., Ltd.) to the coating film surface of the laminate comprising the substrate / adhesive layer (coating film), the tape was peeled off vigorously. The state of the coating film surface was visually observed and evaluated as follows.
○: There was no peeling.
X: There was peeling.
(5) Laminate strength When the base material is a film, a laminate composed of the base material / adhesive layer (coating film) / adhered body is cut out with a width of 15 mm, and one day later, a tensile tester (Intesco Precision Insco Precision Universal) Using a material testing machine 2020, the peel strength was measured at a tensile speed of 200 mm / min and a tensile angle of 180 degrees. When a foam sheet was used, the measurement was performed under the conditions of a tensile speed of 50 mm / min and a tensile angle of 90 degrees.
(6) Blocking resistance After the laminate was allowed to stand in an atmosphere of 30 ° C. for 24 hours in a state where the adhesive layer and the base material layer were superposed, the blocking resistance was evaluated according to the following criteria.
○: Peeled when touched lightly.
(Triangle | delta): It peeled by pulling a film.
X: It did not peel by blocking.

(B) Adhesive raw material (1) Polyether-type polyurethane resin aqueous dispersion (U-1)
Enomoto Kasei Co., Ltd., NeoRez R-600, solid content concentration 33 mass%, weight average molecular weight 37,000.
(2) Polyester type polyurethane resin aqueous dispersion (U-2)
Made by Adeka, Adeka Bon titer UX-0666, solid content concentration 40% by mass.
(3) Polycarbonate-type polyurethane resin aqueous dispersion (U-3)
Enomoto Kasei Co., Ltd., NeoRez R-9603, solid content concentration 34 mass%.
(4) Polyester resin aqueous dispersion (E-1)
Unitika, Elitel KZT-8803, solid content concentration 30% by mass.
(5) Polyolefin resin aqueous dispersion (O-1)
Unitika Ltd., Arrow Base SB-1010, solid concentration 25% by mass.
(6) Polylactic acid resin aqueous dispersion (P-1)
Daiichi Kogyo Seiyaku Co., Ltd., Prasema L110G, solid content concentration 52 mass%.
(7) Terpene-based tackifier aqueous dispersion (T-1)
Yasuhara Chemical Co., Ltd. Nanolet R-1050, solid content concentration 50 mass%.
(8) Candelilla wax aqueous dispersion (W-1)
Unitika, wax emulsion CAW-30M, solid content concentration 30% by mass.

(C) Base material and adherend (1) Biaxially stretched polylactic acid film (product name: Terramac film TFE-25, thickness 25 μm, manufactured by Unitika).
(2) Polylactic acid-based foam sheet A polylactic acid-based resin (manufactured by Unitika, HV-6250H) was supplied to a biaxial kneaded extruded foam manufacturing apparatus (TEM-48BS manufactured by Toshiba Machine). Melting was performed at a temperature of 200 ° C., and 1.4% by mass of carbon dioxide gas was added at a discharge rate of 100 kg / h to prepare a uniform foam sheet composed of closed cells with an expansion ratio of 6.0 times and a thickness of 2.2 mm.
(3) Unstretched polypropylene film (Toray Synthetic Films, Trefan NO ZK93K, thickness 50 μm).

Example 1
The polyether type polyurethane resin aqueous dispersion (U-1) is used as the adhesive, the biaxially stretched polylactic acid film is used as the base material, and the aqueous dispersion (U-1) is added to the corona-treated surface. It apply | coated so that the film thickness after drying might be set to 1 micrometer, it was made to dry at 120 degreeC for 1 minute, and the laminated body which consists of a base material / adhesion layer (coating film) was obtained. The adhesion of the obtained laminate was good.
A biaxially stretched polylactic acid film is used as a substrate, and an aqueous adhesive (U-1) is applied to this corona-treated surface so that the film thickness after drying is 4 μm, and dried at 120 ° C. for 1 minute. A laminate comprising a substrate / adhesive layer (coating film) was obtained. Next, the adhesive layer of the obtained laminate and the non-stretched polypropylene film as the adherend were bonded so that the corona-treated surface was in contact with the adhesive layer, and a heat press (sealing pressure 0.2 MPa for 5 seconds) It pressed at 100 degreeC and obtained the laminated body which consists of a base material / adhesion layer / adherence body. The laminate strength of the obtained laminate was 1.1 N / 15 mm.

Examples 2 to 4, Comparative Examples 1 and 2
The polyether type polyurethane resin aqueous dispersion (U-1) and the polylactic acid resin aqueous dispersion (P-1) are shown in Tables 1 and 2 in terms of mass parts of polyurethane resin solids and polylactic acid resin solids. It mixed so that it might become a mass part, and also water was added, and the aqueous adhesive with a solid content concentration of 30 mass% was prepared.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Examples 5-7, Comparative Examples 3, 4
The polyether type polyurethane resin aqueous dispersion (U-1) and the terpene-based tackifier aqueous dispersion (T-1) have a polyurethane resin solid content and a terpene-based tackifier solid content in parts by mass as shown in Tables 1 and 2. The mixture was mixed so as to have a mass part described in 1. and water was further added to prepare an aqueous adhesive having a solid content concentration of 30% by mass.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Examples 8 to 13, Comparative Examples 5 and 6
The polyether-type polyurethane resin aqueous dispersion (U-1), the polylactic acid-based resin aqueous dispersion (P-1), and the terpene-based tackifier aqueous dispersion (T-1), It mixed so that it might become a mass part as described in Table 1, 2, and water was added, and the aqueous adhesive with a solid content concentration of 30 mass% was prepared.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Example 14
Using an unstretched polypropylene film as a substrate, the aqueous adhesive used in Example 8 was applied to this corona-treated surface so that the film thickness after drying was 4 μm, and dried at 60 ° C. for 1 minute. A laminate comprising a substrate / adhesive layer (coating film) was obtained. Subsequently, the adhesive layer of the obtained laminate and the polylactic acid-based foamed sheet as the adherend were bonded together and pressed at 60 ° C. with a heat press machine (sealing pressure of 0.2 MPa for 5 seconds). A laminate comprising material / adhesive layer / adherent was obtained. The laminate strength of the obtained laminate was 1.4 N / 15 mm.
By applying thermoforming to the obtained laminate, it could be formed into a saddle shape.

Examples 15-18, Comparative Example 7
The polyether-type polyurethane resin aqueous dispersion (U-1) and the candelilla wax aqueous dispersion (W-1) were mixed so that the mass parts of the respective solids were the mass parts described in Tables 1 and 2. Further, water was added to prepare an aqueous adhesive having a solid content concentration of 30% by mass.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Example 19, Comparative Example 8
The polyether-type polyurethane resin aqueous dispersion (U-1), the polylactic acid-based resin aqueous dispersion (P-1), and the candelilla wax aqueous dispersion (W-1) are shown in Table 1. 2 was mixed, and water was further added to prepare an aqueous adhesive having a solid content concentration of 30% by mass.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Example 20, Comparative Example 9
The polyether type polyurethane resin aqueous dispersion (U-1), the terpene-based tackifier aqueous dispersion (T-1), and the candelilla wax aqueous dispersion (W-1) are represented by mass parts of respective solids. The mixture was mixed so as to have the mass parts described in 1 and 2, and water was further added to prepare an aqueous adhesive having a solid content concentration of 30% by mass.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Example 21, Comparative Example 10
Polyether-type polyurethane resin aqueous dispersion (U-1), polylactic acid-based resin aqueous dispersion (P-1), terpene-based tackifier aqueous dispersion (T-1), and candelilla wax aqueous dispersion (W- 1) was mixed so that the mass part of each solid content was the mass part described in Tables 1 and 2, and water was further added to prepare an aqueous adhesive having a solid content concentration of 30 mass%.
Using the obtained water-based adhesive, a laminate and a laminate were obtained in the same manner as in Example 1, and each characteristic was measured.

Comparative Examples 11-14
Instead of the polyether type polyurethane resin aqueous dispersion (U-1), the polyester type polyurethane resin aqueous dispersion (U-2), the polycarbonate type polyurethane resin aqueous dispersion (U-3), and the polyester resin aqueous dispersion (E -1) The same procedure as in Example 10 was carried out except that the aqueous polyolefin resin dispersion (O-1) was used.

  The evaluation results of Examples 1 to 21 and Comparative Examples 1 to 14 are shown in Tables 1 and 2.

The aqueous adhesives obtained in Examples 1 to 13 had good adhesion and pot life, and were excellent in laminate strength. By using a three-component system, the laminate strength was remarkably improved (Examples 8 to 13). Moreover, it became clear that even if a foam sheet was laminated, an excellent laminate strength was exhibited, and thereafter molding was possible (Example 14). Furthermore, by adding wax, the blocking resistance of the laminate is improved (Examples 15 to 21), and the laminate strength is also improved (Examples 15 to 17). However, when the added amount is increased, the pot life is shortened. Thus, the laminate strength was also lowered (Example 18).
On the other hand, when the polyether type polyurethane resin is not contained as in Comparative Examples 1 to 14, or when the content is small, satisfactory laminate strength cannot be obtained, and the pot life may be shortened. In addition, the laminate strength may decrease due to an increase in the content of the terpene tackifier.

Claims (12)

  An adhesive for polylactic acid resin material, comprising a polyether type polyurethane resin (A).   A polyether type polyurethane resin (A) and a polylactic acid resin (B) are contained, and the mass ratio (A / B) of (A) and (B) is 99/1 to 40/60. A polylactic acid resin adhesive.   It contains a polyether-type polyurethane resin (A) and a terpene tackifier (C), and the mass ratio (A / C) between (A) and (C) is 100/1 to 100/40. Features polylactic acid resin adhesive.   It contains a polyether type polyurethane resin (A), a polylactic acid resin (B), and a terpene tackifier (C), and the mass ratio (A / B) between (A) and (B) is 99 / A polylactic acid resin having a mass ratio of (A), (B), and (C) ((A + B) / C) of 100/1 to 100/40, and 1 to 40/60 Adhesives.   The adhesive according to any one of claims 1 to 4, comprising a wax (D).   The adhesive according to any one of claims 1 to 5, comprising a medium (E).   An adhesive layer comprising the adhesive according to any one of claims 1 to 6, which is formed on a substrate.   A laminate comprising a base material and the adhesive layer according to claim 7.   A laminate comprising: a base material; an adhesive layer according to claim 7; and an adherend laminated on the adhesive layer.   The laminate according to claim 8, wherein the substrate is a polylactic acid resin material or a polyolefin resin material.   The laminate according to claim 9, wherein the substrate and / or the adherend is a polylactic acid resin material and / or a polyolefin resin material.   A polyether type polyurethane resin (A) aqueous dispersion, a polylactic acid resin (B) aqueous dispersion and / or a terpene tackifier (C) aqueous dispersion and / or a wax (D) aqueous dispersion, The method for producing an adhesive according to claim 6, wherein mixing is performed.