JPH05339557A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a hot-melt adhesive compsn. which is easily biodegradable, excellent in applicability and instant adhesion properties, and useful for the bonding of a biodegradable plastic by using a thermoplastic resin and a tackifier as the main components, incorporating a specific compd. into either or both of the main components, and specifying the melt viscosity of the compsn. CONSTITUTION:A hot-melt adhesive compsn. is prepd. by using a thermoplastic resin and a tackifier as the main components, incorporating poly(lactic acid) or a lactic acid copolymer resin obtd. from lactic acid and another hydroxycarboxylic acid into either or both of the main components [e.g. a high-molecular poly(D, L-lactic acid) obtd. by the dehydropolycondensation of a D, L-lactic acid as the thermoplastic resin and a poly(lactic acid) having both molecular ends blocked by methyl ester groups and obtd. by the dehydropolycondensation of a D, L-lactic acid wit methyl lactate as the tackifier], and adjusting the melt viscosity of the compsn. to 10-300,000cp at 180-210 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt adhesive suitable for recycling and biodegradable plastics and capable of being melted, discharged or applied, and then lightly pressed for adhesion. More specifically, the present invention relates to a hot melt adhesive composition, which comprises a hot melt adhesive composition that necessarily contains a lactic acid polymer, exhibits alkaline water disintegration or microbial degradability properties, and is particularly best suited for adhesion of biodegradable plastics.

[0002]

2. Description of the Related Art Conventionally, hot melt adhesives have been used at room temperature at 10
It is 0% solid, melts by heating, and has the property of instantly adhering just by cooling and fixing after application. It is widely known as a labor-saving instant adherable adhesive, such as bookbinding, bagging, It has been widely used as a labor-saving adhesive in a wide range of fields such as woodworking and automobile interior and exterior. In particular, polyolefin resin such as ethylene-vinyl acetate copolymer, styrene block copolymer, butyl rubber, ethylene-ethyl acrylate copolymer and ionomer resin, polyester, polyamide resin and the like are used as the thermoplastic base polymer, and other petroleum-based tackifiers and wax are the main components. The low- to high-viscosity hot melt adhesives are most popular and are mainly used in the above fields. However, in recent years resource saving,
From the perspective of pollution-free, there is a need for recycling suitability of adhesive products and short-term disintegration in a natural environment.
In the conventional hot melt adhesive as described above, the general property thereof is that hydrolyzable property and microbial degradable property are extremely slow, and thus lack of adaptability is a problem at present. That is, various adhesive products using a conventionally known hot melt adhesive have a sufficient adhesive function for several years under normal handling conditions, and when reused, the adhesive is easily decomposed and deteriorated by some method. However, there is a problem that it is not enough to have the function of restoring the bonding interface to the state before the bonding. Further, at the same time as the recycling suitability, the microbial degradability of the recovered hot melt adhesive and the low toxicity of its degrading components, etc.
The reality of hot melt adhesives that can sufficiently meet such demands is not yet perfect. As a conventionally known prior art, there is an alkali water-soluble hot melt adhesive hot melt adhesive containing a maleic anhydride copolymer as an active ingredient in JP-A-4-4279. Further, a polyvinyl alcohol-based water-soluble hot melt adhesive is known. Although such prior art is used as a technique that is suitable for the packaging of corrugated paper boxes, paper boxes, and spine bonding for bookbinding and satisfies the suitability for recovering used paper, its use is limited, and the problem of wastewater treatment and polymer There are difficulties such as lack of collapse of self-confidence. On the other hand, as a recycling technology to recover the bonded joint to the state before bonding,
For example, there is a method of throwing a bonded product in a large amount of an organic solvent to heat and dissolve the adhesive and peeling and recovering the adhesive, but there is a risk of ignition and ignition due to the solvent and a problem of generation of odor. On the other hand, polylactic acid has been developed as a biodegradable thermoplastic substance, and is disclosed in USP 1,995,970 and USP-3,63.
No. 6,956 discloses the manufacturing method. And polylactic acid is completely consumed in animals within a few months to a year.
It is biodegradable by 100%, and when it is placed in soil or sea water, it starts to decompose in a few weeks in a moist environment, and within 1 to several years it becomes lactic acid, carbon dioxide, and water that are harmless to the human body. It is also known to have. However, a hot melt adhesive composition using polylactic acid having biodegradability, which is rich in coating workability and excellent in instant adhesion suitability and initial adhesive property, and suitable for recycling suitability and adhesion of biodegradable plastic, The substance has not been developed yet.

[0003]

SUMMARY OF THE INVENTION In view of the social background described above, the present invention is excellent in application workability using a polylactic acid-based polymer and is excellent in instant adhesion suitability and initial adhesion properties. It is to develop a hot-melt adhesive composition which is highly recyclable and is suitable for adhering biodegradable plastics, which can be adhered by arbitrarily discharging or applying it to a predetermined place. More specifically, it has a sufficient adhesive function for several years under normal handling conditions, and can be easily decomposed and degraded by some method when reused. Also, have a function to restore the bonding interface to the state before bonding. At the same time, when adhesives such as biodegradable plastics are discarded as they are, they all demonstrate microbial degradability including hot-melt adhesives, and their degradative components are for human bodies and natural creatures.
There should be no toxicity or the impact on the environment should be extremely slight. It is the development of a hot melt adhesive that can sufficiently meet the demands of the above.

[0004]

Means for Solving the Invention As a result of intensive studies for the purpose of solving the above-mentioned problems, the present inventors have achieved the present invention by using polylactic acid or a polylactic acid-based polymer in a specified mode. Achieved That is, the present invention is as follows. (1) A composition containing a thermoplastic resin and a tackifier as main components, and one or both of them containing polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, and a system thereof. Melt viscosity of 180-210
A hot melt adhesive composition, which is in the range of 10 to 300,000 centipoise at 0 ° C. (2) Part or all of the thermoplastic resin and / or the tackifier is derived from L-type and / or D-type polylactic acid, or L-type and / or D-type lactic acid and other hydroxycarboxylic acid The hot melt adhesive composition according to the above 1, which is a lactic acid copolymer resin. (3) A modified polymer in which the thermoplastic resin is composed of any one or a mixture of two or more of the following (a) to (f) and has a weight average molecular weight of at least 10,000 or more. It is a modified polylactic acid, the tackifier is composed of any one or a mixture of two or more of the following (a) to (f), and its weight average molecular weight is at least 5,000 or less. 3. The hot melt adhesive composition according to 1 or 2 above, which is a low molecular weight modified polylactic acid resin. (A) Polyuric acid or a urethanized polyacetal obtained by reacting a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid with a diisocyanate compound at a molar ratio of 2: (1 to 0.9) Lactic acid. (B) Obtained by dehydration condensation reaction of polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and a diol compound or dicarboxylic acid at a molar ratio of 2: (1 to 0.9). Esterified polylactic acid. (C) Epoxy-modified polylactic acid obtained by reacting polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid with a diglycidyl compound in a molar ratio of 2: (1 to 0.9). (D) A molar ratio of the diisocyanate compound to the same molar amount of the polylactic acid or the lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and the alkyl lactate (1: 1) :( 1 to The urethane-modified polylactic acid obtained by reacting at a ratio of 0.9). (E) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, or (a) to
A silylated polylactic acid obtained by introducing a hydrolyzable silyl group at the molecular end of (d). (F) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid or the above (a) to
End-esterified polylactic acid obtained by blocking the molecular end of (d) with an alkyl ester. (4) The thermoplastic resin has a weight average molecular weight of 2 to 10
70 to 5% by weight of polylactic acid or lactic acid copolymer resin or polymer-modified polylactic acid in the range of 0,000, and polylactic acid or lactic acid copolymer resin having a weight average molecular weight of at most 5,000 or less as a tackifier or low. 95-3 of molecular modified polylactic acid
The hot melt adhesive composition according to any one of 1 to 3 above, which is 0% by weight. (5) The tackifier has a weight average molecular weight of 3,000.
30 to 90% by weight of the following polylactic acid or lactic acid copolymer resin or low molecular weight modified polylactic acid, and a polylactic acid or lactic acid copolymer resin or polymer modified with a weight average molecular weight of 70 to 500,000 as a thermoplastic resin. 10 to 70% by weight of the high-quality polylactic acid, and one component of the tackifier, polylactic acid or lactic acid copolymer resin or polymer-modified polylactic acid as the thermoplastic resin has a hydroxyl value or acid value of 1 or less. The hot melt adhesive composition according to any one of 1 to 3 above. (6) All of the hydroxyl value or acid value of polylactic acid or lactic acid copolymer resin or polymer-modified polylactic acid is 0.1.
The hot melt adhesive composition according to any one of the above 1 to 4, characterized in that: (7) The thermoplastic resin is polyamide, polyester,
1 to 6 above, which is used alone or in combination with at least one kind selected from polyester urethane, polycarbonate, and polyolefin, or polylactic acid or lactic acid copolymer resin which is also a thermoplastic resin, or polymer modified polylactic acid. 7. The hot melt adhesive composition according to any one of 3 and 6. (8) The tackifier is a rosin ester and / or a terpene-phenol resin alone in the range of 20 to 70% by weight, or a polylactic acid or a lactic acid copolymer resin or a low molecular weight modified polylactic acid which is also a tackifier. The hot melt adhesive composition according to any one of the above 1 to 3, 6, and 7, which is used in combination. (9) At least one selected from natural wax, ester amide wax and polyester wax in addition to the hot melt adhesive composition according to any one of 1 to 8 above.
A hot-melt adhesive composition containing various wax components and / or a polylactic acid compatibilizing plasticizer in the range of 0.1 to 50% by weight. (10) A bonding method comprising using the hot melt adhesive composition according to any one of 1 to 9 above for bonding biodegradable bioplastics to each other.

The present invention will be described in detail below. For the purpose of the invention, the hot-melt adhesive composition of the present invention comprises a polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, either or both of a thermoplastic resin component and a tackifier component. The most characteristic feature of the hot melt adhesive composition is an alkali water disintegratable or microbial degradable hot melt adhesive composition having a melt viscosity of 180 to 210 ° C. in the range of 10 to 300,000 centipoises. For hot-melt adhesives composed of only one of the above-mentioned thermoplastic resins and tackifiers, and for systems exceeding 300,000 centipoise or less than 0.0010,000 centipoise, adhesive coating workability and practical adhesion This is because the physical properties are not sufficiently satisfied, and more specifically, the wettability and the coating work characteristics cannot be sufficiently satisfied only by the thermoplastic resin, and the adhesive is extremely brittle and hardly practical with only the tackifier. In the present invention, the polylactic acid or the lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid is used as either one of the components, specifically, the thermoplastic resin or the tackifier as one of the components. To contain L-type and / or D-type polylactic acid or a lactic acid copolymer resin derived from L-type and / or D-type lactic acid and other hydroxycarboxylic acid. Particularly preferably, L-type and / or D-type polylactic acid or a lactic acid copolymer resin derived from L-type and / or D-type lactic acid and other hydroxycarboxylic acid is used as all components of the thermoplastic resin and the tackifier. It is preferable to include it. The L-type, D-type, LD-complex type polylactic acid described in the present invention or a lactic acid copolymer resin derived from L-type and / or D-type lactic acid and another hydroxycarboxylic acid (hereinafter, lactic acid copolymer resin is simply referred to as lactic acid A compound obtained by the following method is mentioned as a typical example, and is generally referred to as a copolymer.
Further, after obtaining a product obtained by directly dehydrating and polycondensing lactic acid of D-form or D-form or a mixed lactic acid thereof, or a product generally called lactide synthesized from the cyclic dimer of lactic acid, the lactic acid is further developed. Examples thereof include those obtained by ring polycondensation. The lactic acid and the lactic acid copolymer derived from other hydroxycarboxylic acid may be a mixture of L-type and / or D-type lactide partially containing the lactic acid, or the lactide alone and ε-caprolactone or glycolide. It also includes a lactic acid copolymer derived from a copolymerizable monomer, and there is no particular limitation on the synthetic means thereof, and polylactic acid or lactic acid copolymer obtained by a known method can be preferably used.

In the present invention, the polylactic acid or lactic acid copolymer is modified as shown in (a) to (f) below for the purpose of improving and stabilizing the thermal stability and adhesive properties of the adhesive composition. Low or polymer modified polylactic acid is preferable. In the following description, low molecular weight modified polylactic acid means a substance classified and defined as a tackifier component, while polymer modified polylactic acid means a substance classified and defined as a thermoplastic resin component. .. (A) Polyuric acid or a urethanized polyacetal obtained by reacting a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid with a diisocyanate compound at a molar ratio of 2: (1 to 0.9) Lactic acid is, for example, a low- or high-molecular weight urethane-modified poly (lactic acid) obtained by reacting polylactic acid or a lactic acid copolymer with a diisocyanate compound, which is obtained by subjecting one end hydroxyl group of so-called polylactic acid or lactic acid copolymer to urethane modification. Examples of the lactic acid include low- or high-molecular weight urethanized polylactic acid obtained by reacting polylactic acid or a lactic acid copolymer with a known diisocyanate compound at a molar ratio of 2: (1 to 0.9). .. As the diisocyanate compound, known compounds may be used, and the following compounds are typical examples, although they are not particularly limited. For example, naphthalene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenyl methane diisocyanate, tetramethyl xylylene diisocyanate and other aromatic diisocyanates, and isophorone diisocyanate, tetramethylene diisocyanate and other aliphatics There are diisocyaners and the like. (B) Obtained by dehydration condensation reaction of polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and a diol compound or dicarboxylic acid at a molar ratio of 2: (1 to 0.9). Esterified polylactic acid refers to, for example, a low or high polylactic acid or lactic acid copolymer obtained by reacting a diol compound or a dicarboxylic acid with a so-called polylactic acid or lactic acid copolymer obtained by esterifying and modifying a carboxyl group at one terminal. It is an esterified polylactic acid having a molecular weight, and the polylactic acid or lactic acid copolymer and a known diol compound or dicarboxylic acid are used in a molar ratio of 2: (1
The low- or high-molecular-weight esterified polylactic acid obtained by the dehydration-condensation reaction at a ratio of up to 0.9) is included. As the diol compound, known compounds may be used, and the following compounds are typical examples although they are not particularly limited. For example, glycols represented by ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A and bisphenol. F or its ethylene and / or propylene adduct and the like can be mentioned.

As the above-mentioned dicarboxylic acid, known products may be used, and the following products are typical examples although they are not particularly restricted. Examples thereof include aliphatic dicarboxylic acids represented by succinic acid, maleic acid, propionic acid, and the like, and aromatic aromatic dicarboxylic acids represented by phthalic acid and fumaric acid. (C) Epoxy-modified polylactic acid obtained by reacting polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid with a diglycidyl compound at a molar ratio of 2: (1 to 0.9) Is, for example, low- or high-molecular weight epoxy-modified polylactic acid obtained by reacting polylactic acid or a lactic acid copolymer with a diglycidyl compound, which is obtained by reacting and modifying a so-called polylactic acid or lactic acid copolymer with a carboxyl group at one terminal with a glycidyl group. And the epoxy-modified polylactic acid obtained by subjecting polylactic acid or a lactic acid copolymer and a known diglycidyl compound to a dehydration condensation reaction at a molar ratio of 2: (1 to 0.9). As the diglycidyl compound, known compounds may be used, and the following compounds are typical examples, although they are not particularly limited. For example, bisphenol A or bisphenol F type diglycidyl ether epoxy resin, aromatic diglycidyl compound represented by naphthalene diglycidyl ether, neopentyl diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether. Diglycidyl compounds of glycols represented by ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and 1,4-butanediol diglycidyl ether, and other alicyclic diglycidyl compounds. Be done. (D) A molar ratio of the diisocyanate compound to the same molar amount of the polylactic acid or the lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and the alkyl lactate (1: 1) :( 1 to The urethane-modified polylactic acid obtained by reacting at a ratio of 0.9) is, for example, the same mole of polylactic acid or lactic acid copolymer and lactic acid alkyl ester (hereinafter, lactic acid alkyl ester is simply referred to as alkyl lactic acid in the present invention). Obtained by reacting the diisocyanate compound with respect to the amount, so-called polylactic acid or lactic acid copolymer and one terminal hydroxyl group of the alkyl lactic acid is modified by reaction with an isocyanate group, to the terminal molecule via the diisocyanate compound. Low or high molecular weight urethane with one polylactic acid or lactic acid copolymer and one alkyl lactic acid Modified polylactic acid and low- or high-molecular-weight urethane-modified polylactic acid in which polylactic acid or an alkyl lactic acid adduct of a lactic acid copolymer is bonded to the terminal molecule through the diisocyanate compound, respectively, may be mentioned. The urethane-modified polylactic acid obtained by subjecting the known diisocyanate compound to a condensation reaction at a molar ratio of (1: 1) :( 1 to 0.9) with respect to the same molar amount of alkyl lactic acid can be mentioned. ..

The alkyl lactic acid is not particularly limited, but alkyl lactic acid having 30 or less carbon atoms, preferably 18 or less carbon atoms, preferably 5 or less carbon atoms is preferable.
Methyl lactate (also known as methyl 2-hydroxypropanoate),
Ethyl lactate (also known as ethyl 2-hydroxypropanoate),
Propyl lactate (also known as propyl 2-hydroxypropanoate) and butyl lactate (also known as butyl 2-hydroxypropanoate) are preferred examples because they are easily available. The method for obtaining a low- or high-molecular-weight urethane-modified polylactic acid in which polylactic acid or a lactic acid copolymer and an alkyl lactic acid are bound to the terminal molecule through the diisocyanate compound is not particularly limited, but for example, polylactic acid Alternatively, an equimolar amount of a diisocyanate compound showing different properties in the active reaction rate of an isocyanate group represented by, for example, tolylene diisocyanate with respect to a lactic acid copolymer or an alkyl lactic acid is slowly acted, and then the other A typical example is a method in which a molar amount is used to obtain the compound. The method for obtaining a low- or high-molecular urethane-modified polylactic acid in which alkyl lactic acid adducts of polylactic acid are respectively bonded to terminal molecules via the diisocyanate compound is not particularly limited, but for example, polylactic acid and alkyl After the esterification reaction of equimolar amount of lactic acid completely or after the esterification reaction of equimolar amount of lactic acid copolymer and alkyl lactic acid, further slowly equimolar amount of the diisocyanate compound to the reaction product. A typical example is a method of obtaining it. (E) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, or (a) to
The silylated polylactic acid obtained by introducing a hydrolyzable silyl group at the molecular end of (d) is, for example, polylactic acid or a lactic acid copolymer, or the active hydroxyl group and / or active carboxyl group at the molecular end of (a) to (d) above. A di- or trimethoxysilane monomer represented by trimethoxyepoxysilane, dimethoxymethylepoxysilane, trimethoxyisocyanatosilane, dimethoxymethylisocyanatosilane, or triethoxyepoxysilane, dietoxymethyl that can react with a group. Epoxy silane,
A typical example is low- or high-molecular-weight silylated polylactic acid obtained by reacting alkoxysilane monomers such as di- or triethoxysilane derivatives represented by triethoxyisocyanatosilane.

(F) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid, or a terminal-esterified polylactic acid obtained by blocking the molecular ends of the above (a) to (d) with an alkyl ester. Examples thereof include polylactic acid, lactic acid copolymer, and low- or high-molecular-weight end-esterified polylactic acid obtained by blocking the molecular ends of the above (a) to (d) with alkyl ester. May be an already known alkyl esterifying agent capable of reacting with an active hydroxyl group and / or an active carboxyl group at one end of polylactic acid, and there is no particular limitation, but the followings are typical examples. .. For example, the alkyl esterifying agent acting on the active carboxyl group at one end of polylactic acid is not particularly limited, but is an aliphatic or aromatic alcohol having 30 or less carbon atoms, preferably 18 or less carbon atoms, preferably 5 or less carbon atoms. There are kinds. On the other hand, as the alkyl esterifying agent acting on the active hydroxyl group at one end of polylactic acid, there is no particular limitation, but aliphatic or aromatic acids having 30 or less carbon atoms, preferably 18 or less carbon atoms, preferably 5 or less carbon atoms. And other alkyl lactic acid mentioned above. In the present invention, the above (a)
-(F) The modified polylactic acid resin described in (f) is used alone or in combination, so that the hot melt adhesive composition of the present invention has suitable wetting characteristics for an adherend, suitable alkaline water disintegration property, The properties such as the rate of microbial degradability can be adjusted or achieved arbitrarily, and therefore, it is essential to appropriately select and use the modified polylactic acid resin described in (a) to (f) according to the purpose. It is conventional in achieving the invention. Particularly, the hot melt adhesive composition of the present invention, which is suitable for use in adhering biodegradable plastics to pottery, glass, metal, paper, wood, etc., includes polylactic acid or lactic acid copolymer and the above (a) to (f). It is preferable to use the modified polylactic acid resin described above, particularly preferably polylactic acid or the modified polylactic acid resin described in (e), as the thermoplastic resin component or tackifier component of the present invention. Further, as the hot melt adhesive composition of the present invention particularly suitable for adhering biodegradable plastics to each other, the modified polylactic acid resin described in the above (a) to (f) including polylactic acid or lactic acid copolymer is particularly preferable. Is a highly preferred embodiment in which polylactic acid or the modified polylactic acid resin described in (f) is used as the thermoplastic resin component or tackifier component of the present invention.

In the present invention, hereinafter, the polylactic acid or the lactic acid copolymer of lactic acid and other hydroxycarboxylic acid and the modified polylactic acid resin, which have been described above, are collectively referred to simply as polylactic acid resin. And Other hydroxycarboxylic acids described in the present invention can be preferably used as long as they are already known, and there is no particular limitation, but the followings are typical examples. For example, glycolic acid,
3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid and 6-hydroxycaproic acid can be preferably used, and glycolic acid is a particularly preferable example. Especially in the hot-melt adhesive composition of the present invention using a lactic acid copolymer obtained from lactic acid and other hydroxycarboxylic acid as a polylactic acid resin, the property of hydrolysis is slightly delayed, and the property of biodegradability is pure polylactic acid. (Meaning of polymer derived from 100% lactic acid only), it is a very preferable example because it is almost the same. In the present invention, a lactic acid copolymer obtained from lactic acid and the above-mentioned other hydroxycarboxylic acid is used as a starting material, and a hot polylactic acid resin modified / derived by the modifying means described in (e) or (f) above is used. A melt adhesive composition or a lactic acid copolymer of lactic acid and the other hydroxycarboxylic acid as described above is used as a starting material, and further, alone or in the presence of the above-mentioned allylic lactic acid in an equimolar amount with the lactic acid copolymer,
A hot melt adhesive composition or the like using a polylactic acid resin modified / derived by the modifying means described in (a) slightly delays the property of hydrolysis, and the property of microbial degradability is pure polylactic acid (100). % Is the same as the meaning of a polymer derived only from lactic acid), which is a highly preferred embodiment.
Further, the high-molecular weight polylactic acid resin classified and defined as the thermoplastic resin of the present invention means a product having a weight average molecular weight measured value of 10,000 or more, preferably 21 to 1,000,000, particularly preferably 70 to 500,000. It is preferably within the range. Low molecular weight polylactic acid resins of 10,000 or less are classified and defined as tackifier components in the present invention. On the other hand, when it is used as a tackifier component, it has a weight average molecular weight of 10,000 or less, preferably 5,000 or less, and particularly preferably 3,000 or less, as mentioned above, and may be a cyclic lactide of lactic acid.

In the hot melt adhesive composition of the present invention,
The thermoplastic resin may be any one component or a composite component of a high molecular weight polylactic acid resin having a weight average molecular weight of 10,000 or more and other known thermoplastic resins. The ratio of their use as a thermoplastic resin is 70 to 5
In the range of wt%, preferably a high-molecular weight polylactic acid resin having a weight average molecular weight of 1 to 1,000,000 as a thermoplastic resin is used alone or in combination with another thermoplastic resin in the above ratio, particularly preferably, The use of a high molecular weight polylactic acid resin having a weight average molecular weight in the range of 70,000 to 500,000 as the plastic resin alone in the range of 70 to 10% by weight is a preferred embodiment from the viewpoint of workability for adhesive coating and adhesion reliability. .. In particular, the weight average molecular weight is in the range of 70,000 to 500,000 and the hydroxyl value or acid value is at most 1 or less, preferably 0.
The use mode of 1 or less is a particularly preferred mode because it can improve the thermal stability and hue stability of the composition of the present invention. In the hot-melt adhesive composition of the present invention, what is used as a tackifier is any one component or a composite component of a low molecular weight polylactic acid resin having a weight average molecular weight of 10,000 or less and other known tackifiers. It doesn't matter. The proportion of those used as a tackifier is in the range of 95 to 30% by weight,
The thermoplastic resin preferably has a weight average molecular weight of 5,0.
A low molecular weight polylactic acid resin of 00 or less is used alone or in combination with another thermoplastic resin in the above ratio, and particularly preferably, a low molecular weight polylactic acid resin having a weight average molecular weight of 3,000 or less is used as a tackifier. It is a preferred embodiment from the viewpoint of adhesive wetting properties that it is used alone in the range of 90 to 30% by weight. In addition, the above-mentioned use mode in which the weight average molecular weight is 3,000 or less and the hydroxyl value or the acid value is at most 1 or less, preferably the acid value is 0.1 or less is the heat stability and the hue of the composition of the present invention. This is a particularly preferred embodiment because the stability can be improved. In particular, the use mode in which the polylactic acid resin, which is either a thermoplastic resin or a tackifier, has a hydroxyl value or an acid value of 1 or less, and preferably 0.1 or less is a most preferable embodiment. The reason is
Although the present invention is not limited in the constitution in which the two types of polylactic acid molecule terminal groups respectively have a carboxyl group and a hydroxyl group, they react with each other in a molten state at 180 to 210 ° C. and a viscous behavior occurs during dissolution. This is because there are cases in which the thermal stability is not constant and does not satisfy.

In the present invention, as already mentioned above, some of the other thermoplastic resins described below (in the following description, the other thermoplastic resins are simply referred to as base polymers in the sense of being distinguished from the high molecular weight polylactic acid resin) Or the use alone is included. That is, for example, the base polymer described below may be used alone, and the tackifier may contain a polylactic acid resin as an essential component, or vice versa. The base polymer is not particularly limited in properties such as its kind, molecular weight, compatibility with polylactic acid resin (polymer blend stability), and known base polymers can be used. It is preferable that the polylactic acid resin is partially or completely compatible, and the present invention can be achieved by appropriately selecting and using a base polymer having high polymer blend stability. Known base polymers, for example, ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin, ethylene-copolymer resin represented by ethylene-butene resin, butyl rubber,
Examples thereof include natural rubber, polyolefin rubber represented by polyisobutylene, polystyrene resin, polyethylene resin, polypropylene resin, and polyolefin represented by styrene block copolymer resin. Other examples include polyamide, polyester, polyurethane, polyimide, acrylic resin, ionomer resin and the like. Preferable examples include polyamide, polyester, polyester urethane, polycarbonate, and polyolefin, and an embodiment in which at least one of them is used alone or in combination with a high molecular weight polylactic acid resin is preferable.

When the base polymer and the high-molecular-weight polylactic acid resin are used in combination, the blending ratio is such that the melt viscosity of the hot-melt adhesive of the present invention is in the range of 10 to 300,000 centipoises measured at 180 to 210 ° C. It is preferable to use them, and the combination ratio may be arbitrary. However, the higher the proportion of the polylactic acid resin used is, the higher the alkaline water disintegration property and the higher biodegradability of the composition (or that the composition of the present invention that can be easily and easily recycled) can be obtained. Needless to say. The present invention includes the use of the other tackifiers described below in part or alone as already described above. That is, for example, the other tackifiers described below (in the following description, the other tackifiers are simply called tackifiers to distinguish them from low-molecular-weight polylactic acid) are used alone, and an essential component for the thermoplastic resin is used. And a mode of containing a polylactic acid resin which is
The opposite may be true. The tackifier is not particularly limited in its properties such as type, molecular weight, compatibility with polylactic acid resin (polymer blend stability), and may be a known tackifier. It is preferable that it is partially or completely compatible with the polylactic acid resin, and any tackifier that exhibits the effect of lowering the viscosity of the thermoplastic resin component when heated can be preferably used.

Known as a tackifier, for example,
Rosin or its derivative, terpene resin and its derivative,
Petroleum resins derived from petroleum cracked fractions having 5 to 9 carbon atoms,
Dicyclopentadiene resin, coumarone-indene resin,
Ketone resin, xylene resin, acrylic onogomer resin,
There are polyester oligomer resins and the like, and other well-known biodegradable oligomers other than polylactic acid are also mentioned. Generally, at room temperature, solid or semi-solid or liquid number average molecular weight is at most several thousand or less, preferably 5, The low molecular weight resin having a molecular weight of 000 or less can be used. The known biodegradable resin oligomers other than polylactic acid include, for example, oligomers such as 3-hydroxybutyric acid and 3-hydroxyvaleric acid and copolymerized oligomers thereof, and further ring-opening oligomer resin resin of ε-caprolactone. Is mentioned. Particularly preferred tackifiers include rosin esters and / or terpene-phenol resins, the proportion of which is in the range of 20 to 70% by weight,
At the total ratio of using alone or in combination with low molecular weight polylactic acid resin,
A mode in which the above range is set is preferable. In the hot melt adhesive of the present invention, at least one wax component selected from natural wax, ester amide wax and polyester wax and / or 0.1 to 5 is further added to the composition of the above embodiment.
The embodiment containing 0% by weight, preferably 1 to 30% by weight, can improve the adhesive setting time and flexibility of the hot melt adhesive of the present invention, impart appropriate water repellency, etc. It is preferable because the effect of is exhibited. The following are typical examples of the polylactic acid compatibilizing plasticizer, but the compatibilizing plasticizer of the above-mentioned base polymer resin is also included. For example, as a compatibilizing plasticizer for polylactic acid, dioctyl phthalate, dibutyl phthalate, dialkyl phthalate plasticizers represented by diisodecyl phthalate,
Examples thereof include dialkyl adipate plasticizers represented by dioctyl adipate, and di- or triacetate plasticizers represented by glycerin triacetate and neopentyl diacetate. Further, sp-values (solvability parameter values) derived from organic acids such as citric acid and adipic acid, which are in the range of 8 to 9.5, are polyester-based plasticizers, and vegetable oil ester-based plasticizers are also good examples. Particularly preferably, glycerin triacetate-based plasticizers and vegetable oil ester-based plasticizers are mentioned as those exhibiting extremely good compatibility with polylactic acid resin.

The hot melt adhesive composition of the present invention may optionally contain the following additives in advance or immediately before use (at the time of using adhesive). As the additive, known additives such as weather resistance modifiers and fillers such as inorganic substances
Pigments, dyes, heat stability auxiliaries, surfactants, hydrolyzable cocatalysts, microorganisms and fungi that eat organic substances, etc. are also included for the purpose of expressing the original action and effect of these additives over time. It may be partially immobilized or encapsulated (including masking) with the above compound. There are no particular restrictions on the method for adjusting and processing the hot melt adhesive composition of the present invention and the final form thereof, and a known method may be adopted as a general production method, for example, a melt stirring pot or a kneader pot. It is possible to heat and dissolve the respective resin components through the kneading or stirring and dissolving tank. Further, as the take-out processing form, for example, a form such as pellets, blocks, powders, films, sticks, etc., there is no limitation in the processing packaging method for stably storing the processed product until use, and there is no known packaging method. Aspects may be used. There is no limitation on the packaging container, the transportation method, and the like. The point is that the product form may be appropriately determined according to the properties of the hot melt adhesive composition of the present invention such as alkali water disintegration property and microbial degradability. The main adherend using the hot-melt adhesive composition of the present invention is not particularly limited, including biodegradable plastics, metals, stones, ceramics, glass, concrete, gypsum, inorganic substances such as ceramics, wood , Paper, cloth, non-woven fabric,
Plastics and the like can be mentioned, and various kinds of daily necessities and industrial necessities may be targeted. From the main purpose of the present invention, papers, aluminum, glass and biodegradable plastics, which are strongly required to be recycled, are preferable examples of adhesion.

The biodegradable plastic is a plastic which is recognized to be disintegrated by microorganisms existing in nature, especially fungi, and is not particularly limited, but the following substances are already known and preferred examples Is. Examples include polylactic acid, copolymer resins derived from lactic acid and other hydroxycarboxylic acids, copolymer resins of 3-hydroxybutyric acid and 3-hydroxyvaleric acid, polycaprolactone resin, starch-modified industrial plastics, etc. Is mentioned. The hot melt adhesive composition of the present invention can be used not only as the above-mentioned application as an adhesive but also as a color material such as paint, toner and ink (use as a binder for a heat-sensitive color material).

[0017]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. Further,% and parts described in the examples represent% by weight and parts by weight, respectively. Further, each symbol described in the normal adhesive strength section in the table represents the following characteristics. Symbol ◎: Shear peel strength is due to paper break or 5K
g / cm ² or more. ◯: The shear peel strength is such that the probability of breaking the paper is about 10 to 50%, or in the range of ^{2 to 5} kg / cm ² . Δ: When the shear peel strength is an extremely thin surface layer material of paper or is 2 Kg / cm ² or less. Example 1. With respect to the same amount of L-lactic acid and D-lactic acid, 0.3% of tin powder and 0.06% of lauryl alcohol were charged as a catalyst, and the azeotropic temperature of water was 14 in a nitrogen stream under a xylene solvent.
Dehydration polycondensation was carried out at 0 ° C. for 50 hours, and finally solvent removal, decatalysis and filtration were carried out to obtain an LD type polymer polylactic acid (thermoplastic resin-A) having a weight average molecular weight of 46,000. Also separately,
LD (1: 1) mixed lactic acid and methyl lactate were charged, internal temperature 15
By dehydration polycondensation for 3 hours at 0 ° C./reduced pressure, a low molecular weight polylactic acid (tackifier-a) having a weight average molecular weight of 2,200 and having both ends blocked with methyl ester groups was obtained. A transparent colorless composition having a melt viscosity of 180 to 200 ° C. of a hot melt adhesive (a) consisting of 50 parts of the thermoplastic resin-A and 50 parts of the tackifier-a in the range of about 1 to 30,000 centipoise. Met. It should be noted that this hot melt adhesive (a) has a temperature of 190 ° C /
The change in melt viscosity after standing for 24 hours was stable within 10%. This hot melt adhesive (a) was adjusted to 190 ° C. with a hot melt hand gun “Newmelter 90
Adhesion as shown in Table 1 was performed by "mold". In addition, the hot melt handgun "Newmelter 90 type", Nordson's hot melt applicator "Model 2300", and Meltex's hot melt applicator "PS"
In a coating / discharging workability test such as a bead, a surface, or a spray, which was performed with "250" or the like, it was an adhesive that was capable of smoothly coating or discharging an arbitrary amount and had excellent applicator characteristics. The test results of the biodegradability of the hot melt adhesive (a) alone and the hydrolysis with alkaline water are also shown in Table 1.

Example 2. L-lactide 1.5 mol (2
16 parts), 0.01 part of stannous octoate and 0.005 part of stearyl alcohol were charged, and in a nitrogen stream,
The ring-opening polymerization is carried out at a temperature within 185 ° C. to give an L-type polymer polylactic acid having a weight average molecular weight of 103,000 (thermoplastic resin-
B) was obtained. The hot-melt adhesive (b) comprising 40 parts of the thermoplastic resin-B and 60 parts of the tackifier-a obtained in Example 1 has a melt viscosity of about 2 to 180 ° C.
It was a transparent and colorless composition in the range of 50,000 centipoise.
The change in melt viscosity of this hot melt adhesive (b) after standing at 190 ° C. for 24 hours was stable within 10%. This hot melt adhesive (b) was adjusted to 190 ° C with a hot melt handgun "Newmelter-90 type"
Then, the adhesion shown in Table 1 was performed. The results of the coating / discharging workability test similar to those of Example 1 of the hot melt adhesive (b) were good. Also hot melt adhesive (b)
Table 1 also shows the test results of the single biodegradability and the hydrolysis with alkaline water. Examples 3-5. L-lactide 1.5 mol (216 parts)
In place of L-lactide and 108 parts of hydroxycarboxylic acid, L- was prepared in the same manner as in Example 2.
L-type polymer polylactic acid (thermoplastic resin-C, D, E), which is a copolymer of lactide and hydroxycarboxylic acid, was obtained. The case where the hydroxycarboxylic acid is D-lactide is Example 3, the product is the L-type polymer polylactic acid (thermoplastic resin-C) having a weight average molecular weight of 100,000, and the case where the hydroxycarboxylic acid is glycolide is Example 4. The product is a L-type high molecular weight polylactic acid (thermoplastic resin with a weight average molecular weight of 110,000).
D), the case where the hydroxycarboxylic acid is ε-caprolactam is Example 5, and the product is an L-type polymer polylactic acid (thermoplastic resin-E) having a weight average molecular weight of 110,000. Separately, in the same manner as in Example 1, low molecular weight polylactic acid (3,500) having a weight average molecular weight of 3,500 in which both ends are blocked with butyl ester groups from L-lactic acid and butyl lactate A tackifier-b) was obtained. Hot melt adhesive (c) consisting of 40 parts of the thermoplastic resin-C and 60 parts of the tackifier-b, tackifying the same as 40 parts of the thermoplastic resin-D and 40 parts of the tackifier-b A hot-melt adhesive (d) consisting of 10 parts of KE-311, a product of Arakawa Chemical Co., Ltd., which is a transparent rosin ester as an agent, 10 parts of carnauba wax as a wax, 40 parts of a thermoplastic resin-E and a tackifier-
180 of each of the hot-melt adhesive (e) consisting of 10 parts of YS Polystar T-115, a product of Yasuhara Chemical Co., which is a terpene-phenol resin as a tackifier, and 40 parts of beeswax as a wax, similarly to 40 parts of b. The melt viscosity at -200 ° C was generally in the range of about 7,000 centipoise to 35,000 centipoise. In addition, 1 of this hot melt adhesive (C, D, E)
All of the changes in melt viscosity after leaving at 90 ° C. for 24 hours were within 10%, and the adhesive composition was rich in heat stability. The hot melt adhesives (C, D, E) were adhered to each other as shown in Table 1 by using a hot melt hand gun "Numerta-90 type" adjusted to 190 ° C. Table 2 also shows the biodegradability of the hot-melt adhesives (C, D, and E) alone and the test results of alkaline water hydrolysis.

Examples 6-9. LD-mixed (1: 1) lactic acid was charged with 0.3% of tin powder as a catalyst, and vacuum dehydration polycondensation was carried out at an internal temperature of 155 ° C. for 30 hours in the presence of an inert solvent in a nitrogen stream. After filtration, LD type polylactic acid having a weight average molecular weight of 70,000 was obtained. In Example 6, 2,4-tolylene diisocyanate corresponding to 0.5 molar equivalent of polylactic acid was allowed to act on the polylactic acid solution to give a thermoplastic resin having a molecular weight of about 140,000 containing 10% of glycerin triacetate. A urethanated polylactic acid resin-F having a molecular weight was obtained. Example 7
Then, ethylene glycol diglycidyl ether corresponding to 0.5 molar equivalent of polylactic acid is allowed to act on the polylactic acid solution at high temperature for 20 hours to contain 10% of glycerin triacetate, and a thermoplastic polymer having a molecular weight of about 140,000. The epoxy-modified polylactic acid resin-G of was obtained. In Example 8, an ethylene glycol equivalent to 0.5 molar equivalent of polylactic acid was allowed to act on the polylactic acid solution to finally obtain a thermoplastic polymer having a molecular weight of about 140,000 containing 10% of glycerin triacetate. An esterified polylactic acid resin-H esterified with ethylene glycol was obtained. Separately, LD
-Mixed (1: 1) lactic acid was charged, without a catalyst, in a nitrogen stream,
Vacuum dehydration polycondensation at a temperature of 180 ° C. for 2-3 hours,
A low molecular weight LD-type polylactic acid having a weight average molecular weight of 1300 was obtained. Furthermore, the same molar equivalent amount to the low molecular weight polylactic acid, that is, isocyanate triethoxysilane in Example 6, ethyl lactate in Example 7, and 0.5 molar equivalent of xylylene diisocyanate in Example 8, respectively. Low molecular weight silylated polylactic acid (tackifier-
c), low molecular weight esterified polylactic acid (tackifier-
d), low molecular weight urethane polylactic acid (tackifier-e) was obtained. 25 parts of thermoplastic resin-F and tackifier-c30
Parts, 30 parts of tackifier-d, 10 parts of triacetin plasticizer and 5 parts of carnauba natural wax were prepared to prepare a hot melt adhesive composition (f). This hot melt adhesive composition (f) has a melt viscosity at 190 ° C. of about 1.7.
Ten thousand centipoise was exhibited, and the test results of adhesive properties and biodegradability alone and alkaline water hydrolysis are shown in Table-2. Further, thermoplastic resin-F, G, H, tackifier-
From c, d, and e, the hot melt adhesives (Tolu) shown in Table 3 were obtained. All of the hot melt adhesives (G, C, R, N, and L) had a melt viscosity change of 10% or less after being left at 190 ° C. for 24 hours, and thus the adhesive composition was excellent in heat stability.

Example 9. Using 0.35% of tin powder as a catalyst with respect to the same amount of L-lactic acid and D-lactic acid, dehydration polycondensation was performed at a temperature of 154 ° C., which is an azeotropic temperature of water, in a nitrogen stream under an anisole solvent. The LD-type polymer polylactic acid with a weight average molecular weight of 150,000 is obtained by desolvation and filtration, and 0.5 mol equivalent of pure diglycidyl ether of bisphenol A is allowed to act on the polylactic acid. LD type polymer epoxy modified polylactic acid (thermoplastic resin-I) having an average molecular weight of 280,000 was obtained. Separately, LD (1: 1)
Cyclic lactic acid (tackifier-
f) was obtained. Its thermoplastic resin-I, tackifier-f,
From the tackifier, the base polymer, and the tackifier-d obtained in Example 7, hot melt adhesives (wo-yo) shown in Table 4 were prepared. This hot melt adhesive (wo ~
The change in melt viscosity of (i) after standing at 190 ° C for 24 hours is 10
It was stable within%. This hot melt adhesive (wo ~
Table 4 shows the results of the adhesion test of (Y) using a hot melt handgun "Newmelter-90 type" adjusted to 190 ° C. Table 4 also shows the biodegradability of the hot-melt adhesive (wo-yo) alone and the test results of alkaline water hydrolysis. Comparative Example 1. Product name "Evaflex # 220" which is ethylene-vinyl acetate copolymer as the base polymer
(MI value: 400, containing 28% vinyl acetate) 40 parts, 40 parts of Arokawa Chemical's product "rosin ester gum H" as a tackifier, and 20 parts of 75 ° C. paraffin wax have a melt viscosity of 180 ° C. of 1, A 700-centipoise hot melt adhesive composition (X-1) was obtained. The adhesive properties using this hot melt adhesive composition (X-1) and the test results of the single biodegradability and alkaline water hydrolysis are also shown in Table-1. Comparative example 2. Shell chemical product which is styrene-ethylene-propylene-styrene block copolymer as the base polymer, 10 parts of trade name "Clayton G-1652" and 30 parts of trade name "Evaflex A-703" which is ethylene-ethyl acrylate resin. , 20 parts of Arakawa Chemical's trade name "Super Ester A-115" which is a rosin ester as a tackifier and Yasuhara Chemical Co. product which is a terpene resin, trade name YS Resin TO
20 parts of -115, 10 parts of Neowax L as a polyethylene wax, and 1 part of Japan Petroleum Product "Polybutene HV-300" which is liquid polybutene as a plasticizer.
A hot melt adhesive composition (X-2) having 0 parts and a melt viscosity of 180 ° C. of about 10,000 centipoise was obtained. The adhesive properties using this hot melt adhesive composition (X-2) and the test results of the single biodegradability and alkaline water hydrolysis are also shown in Table-2.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

Explanation of Symbols Base Polymer 1: Polyester resin derived from adipic acid and dipropylene glycol and having a weight average molecular weight of about 100,000. Base Polymer 2: Polyamide resin derived from dimer acid having a MI value of 200 at 180 ° C. and hexamethylenediamine. Base polymer 3: dimethyl terephthalic acid and 1,4-
A polyester urethane resin having a weight average molecular weight of 120,000, which is obtained by reacting approximately equivalent moles of isophorone diisocyanate with a polyester oligomer having hydroxyl groups of 1200 and derived from butanediol. Base polymer 4: 2% maleic anhydride modified styrene-ethylene-butylene-styrene block copolymer (1
Resin containing 4% styrene). Base polymer 5: Polyester resin having a weight average molecular weight of about 80,000 obtained by reacting a molar ratio of phthalic acid and adipic acid of 1: 1 with a molar ratio of dipropylene glycol and diethylene glycol of 1: 1. Base polymer 6: Polycarbonate polyol resin having a molecular weight of 10,000. Polyester wax: A synthetic ester wax which is an adduct of tris (2-hydroxyethyl) isocyanurate with 3 behenic acid. Triacetin; glycerin triacetate. Tackifier 1; Arokawa Chemical Co., Ltd. trade name "Super Ester A-115" is used as the rosin ester resin. Tackifier 2; Yasuhara Chemical's trade name "YS" as a low molecular weight terpene-bisphenol A copolymer resin
Polyster T-2115 "is used. Tackifier 3; Melt viscosity term: Low viscosity is 190
The melt viscosity at 0 ° C. is 30,000 or less, and the medium viscosity is in the range of 30,000 to 100,000.

Comparative Example 3. When the biopol material adhesive using the hot-melt adhesive composition (X-3) shown in Table 4 was buried in the soil and dumped, it was taken out and observed several months later. As a result, the biopol material was partially microbial. Although the disintegration progressed and it was in a tattered state, no change was observed in the adhesive, and the bonded shape remained unchanged without change. Also, a paper-cardboard-bonded or aluminum-bonded joint using the hot-melt adhesive composition (X-3) was heated and melted so as to be peeled off again without damaging the material to be bonded, but naturally peeled. It was not possible because the agent only cohesively peeled off. In addition, the same purpose was used in a large amount of heated toluene solvent to dissolve the adhesive and attempt peeling, but the deformation of the paper material was suppressed to some extent, but the adhesive was impregnated and contaminated in the material and its surface. As a result, it was a problem. An attempt was made to peel the interface in weak alkaline water, but no peeling occurred even after immersion for several hours. Example 10. Biopol-equivalent material using the hot-melt adhesive composition (a) obtained in the section of Example 1, when the adhesive was buried in the soil and dumped, it was taken out several months later and observed. The adhesive layer was in a tattered state due to a partial collapse due to microorganisms. In addition, when a joint between aluminum or glass using the hot melt adhesive composition (a) was tried to be peeled again without damaging the material to be bonded, interface peeling in weak alkaline ammonia water was attempted for a short time. Finally, the adhesive was completely hydrated and the material to be bonded could be easily recovered. The treated water required for the stripping treatment was finally an aqueous solution containing a lactate salt that was completely harmless to humans and animals, and was able to be wastewater only by the neutralization treatment.

Embodiment 11. When the biopol-equivalent material adhesives using the hot-melt adhesive composition (h) obtained in Examples 6 to 9 were buried in the soil and discarded, the adhesives containing the biopol material were observed after taking out after several months and observed. The layer was in a tattered state due to some collapse due to microorganisms. In addition, when a joint of aluminum or glass using the hot-melt adhesive composition (h) was tried to be peeled again without damaging the material to be bonded, an attempt was made to remove the interface in slightly alkaline caustic soda water at 30 ° C. By peeling easily within 10 minutes and further washing with water, it was possible to collect a scratch-free material to be adhered with no contamination at the material interface.

Comparative Example 4. A hot melt adhesive mainly composed of an esterified product of polyoxyethylene glycol monomethyl ether, which is a 9-mol addition product of ethylene oxide of a copolymer of maleic anhydride and isobutylene (X-
Using the 200 micron film of 4), aluminum was adhered to each other by heating at 190 ° C. When this bonded product was immersed in a slightly caustic soda aqueous solution at 30 ° C. for 20 minutes, the two aluminum plates were easily peeled off, but the treated water was hot-melt adhesive (X-4), and the esterified product was simply water. It was in a harmony state, and it did not become pollution-free treated water as it was, and complicated neutralization precipitation filtration was essential for wastewater treatment.
In addition, the result of the soil burying test of the single film of the hot melt adhesive (X-4) for 3 months showed that almost no weight change was observed, and it was presumed that the hot melt had no microbial or biodegradable property. Comparative Example 5. The hot melt adhesive (X-5) consisting of polylactic acid having a weight average molecular weight of 100,000 obtained in the same manner as the thermoplastic resin (A) obtained in the section of Example 1 has a melt viscosity of 180,000 or more of 300,000 centipoise or more. It was extremely high, and it was almost impossible to discharge through a hand gun or a hot melt applicator with a built-in melting tank. In addition, we tried to bond paper or biopol-equivalent materials with a hot-melt adhesive (X-5) formed into a film of 100 micron in advance. There was a problem of deformation and discoloration. Hot melt adhesive (X
It has been found that the range in which the adhesive of (5) which has been formed into a film having a thickness of 100 μm in advance can be used is limited to metals and ceramics which can withstand high temperatures, and has a general versatility. Comparative Example 6. With the hot-melt adhesive (X-6) obtained only from the tackifier (a) obtained in the section of Example 1, the 190 ° C. melt viscosity is extremely small, and discharge via a hand gun or a hot-melt applicator with a built-in melting tank is easy. Although it was possible, the property of the product itself was fragile, and even if a material such as paper was adhered, it was easily peeled off, and the practical strength was not satisfied, which was a problem. In particular, when the molded products of polylactic acid polymer film were adhered to each other, only a peel strength of 0.3 kg or less was obtained.

[0029]

As is apparent from Comparative Examples 1 to 3, the present invention cannot exhibit the properties of alkaline water disintegration and biodegradability at all in the conventionally known hot melt compositions, and in particular biodegradation is possible. It is clear that when a resinous resin is used as an adhesion target, if it is dumped into the natural environment as it is, it will not decompose for a very long period of time and cause pollution problems. Comparative Example 4 is an example of an alkaline water-soluble hot melt, which has some recyclability but does not have biodegradable properties and is not an appropriate adhesive for adhering biodegradable plastics and is pollution-free. Not a type. Further, in Comparative Examples 4 and 5, there were cases where hot melt adhesives composed of high molecular weight polylactic acid or low molecular weight oligomers were used, but problems were found in terms of adhesive physical properties and applicator characteristics. It is apparent from Examples 1 to 9 that either or both of the thermoplastic resin component and the tackifier component contain polylactic acid, and the melt viscosity of the system is from 0.001 to 300,000 centipoise at 180 to 210 ° C. Alkaline water-disintegrating or microbial-decomposable hot melt adhesive composition adjusted to the range enables adhesion by melting the adhesive and optionally discharging or applying it to a predetermined place, which is suitable for recycling. It has been found to be a hot melt adhesive composition suitable for adhering rich, biodegradable plastics. In addition, from Examples 10 and 11, the adhesive can be easily decomposed and deteriorated by the method of dipping in alkaline water at the time of reuse, and the function of restoring the joint interface to the state before the adhesion is exhibited. I got the result. At the same time, when the adhesive such as biodegradable plastic is discarded as it is, it exhibits all microbial degradability including hot-melt adhesive, and its degradable components have no toxicity to human body or living organisms in nature. It was also found that the impact on the environment was extremely slight. Therefore, it was judged from the results of the examples that the hot melt adhesive can sufficiently meet the main purpose of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Yashiro Kenichi Yagi Mitsui Toatsu Chemical Co., Ltd. 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa

Claims (10)

[Claims] 1. A composition comprising a thermoplastic resin and a tackifier as main components, and one or both of them containing polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, The melt viscosity of the system is 180
A hot melt adhesive composition, which is in the range of 10 to 300,000 centipoise at 210 ° C. 2. A thermoplastic resin and / or tackifier as a part or all of L-type and / or D-type polylactic acid,
The hot melt adhesive composition according to claim 1, which is a lactic acid copolymer resin derived from L-type and / or D-type lactic acid and another hydroxycarboxylic acid. 3. A thermoplastic resin comprising one or a mixture of two or more of the following (a) to (f) and having a weight average molecular weight of at least 10,000 or more and modified. It is a polymer-modified polylactic acid, the tackifier is composed of any one or a mixture of two or more of the following (a) to (f), and its weight average molecular weight is at least 5000 or less on average. 3. The hot melt adhesive composition according to claim 1 or 2, which is a low-molecular-weight modified polylactic acid resin that is obtained. (A) Polyuric acid or a urethanized polyacetal obtained by reacting a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid with a diisocyanate compound at a molar ratio of 2: (1 to 0.9) Lactic acid. (B) Obtained by dehydration condensation reaction of polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and a diol compound or dicarboxylic acid at a molar ratio of 2: (1 to 0.9). Esterified polylactic acid. (C) Epoxy-modified polylactic acid obtained by reacting polylactic acid or a lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid with a diglycidyl compound in a molar ratio of 2: (1 to 0.9). (D) A molar ratio of the diisocyanate compound to the same molar amount of the polylactic acid or the lactic acid copolymer resin derived from lactic acid and other hydroxycarboxylic acid and the alkyl lactate (1: 1) :( 1 to The urethane-modified polylactic acid obtained by reacting at a ratio of 0.9). (E) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid, or (a) to
A silylated polylactic acid obtained by introducing a hydrolyzable silyl group at the molecular end of (d). (F) Polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid or the above (a) to
A terminal-esterified polylactic acid obtained by blocking the molecular end of (d) with an alkyl ester. 4. A thermoplastic resin having a weight average molecular weight of 2
Polylactic acid or lactic acid copolymer resin or polymer modified polylactic acid of 70 to 5% by weight in the range of up to 1,000,000, and a polylactic acid or lactic acid copolymer resin having a weight average molecular weight of at most 5,000 or less as a tackifier or Low molecular weight modified polylactic acid 9
The hot melt adhesive composition according to any one of claims 1 to 3, which is 5 to 30% by weight. 5. A tackifier having a weight average molecular weight of 3,
30 to 90 wt% of polylactic acid or lactic acid copolymer resin or low molecular weight modified polylactic acid of 000 or less, and polylactic acid or lactic acid copolymer resin or polymer having a weight average molecular weight of 70 to 500,000 as a thermoplastic resin Modified polylactic acid 10-7
0% by weight, and one component of the tackifier, polylactic acid or lactic acid copolymer resin which is a thermoplastic resin, or polymer modified polylactic acid has a hydroxyl value or an acid value of 1
The hot melt adhesive composition according to any one of claims 1 to 3, wherein: 6. The hot melt according to claim 1, wherein the polylactic acid, the lactic acid copolymer resin, or the polymer-modified polylactic acid all have a hydroxyl value or an acid value of 0.1 or less. Adhesive composition. 7. A polylactic acid or a lactic acid copolymer resin or a polymer-modified polylactic acid in which the thermoplastic resin is at least one kind selected from polyamide, polyester, polyester urethane, polycarbonate and polyolefin, or a thermoplastic resin. 7. The hot melt adhesive composition according to claim 1, which is used in combination with. 8. The tackifier comprises a rosin ester and / or a terpene-phenol resin alone in the range of 20 to 70% by weight, or polylactic acid or a lactic acid copolymer resin or a low-molecular modified polyresin which is also a tackifier. The hot melt adhesive composition according to claim 1, which is used in combination with lactic acid. 9. The hot melt adhesive composition according to claim 1, further comprising at least one wax component selected from natural wax, ester amide wax and polyester wax and / or compatibilization of polylactic acid. A hot melt adhesive composition containing a plasticizer in the range of 0.1 to 50% by weight. 10. A bonding method, which comprises using the hot melt adhesive composition according to claim 1 for bonding biodegradable bioplastics to each other.