JP2001294839A - Polyisocyanate curing agent for adhesive for laminate, and adhesive for laminate by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyisocyanate curing agent for an adhesive for laminate excellent in stability with time, and further excellent in heat resistance, durability and especially adhesion to a metallic film and a polyolefin film, and further to provide an adhesive for laminate by using the curing agent. SOLUTION: This polyisocyanate curing agent for the adhesive for laminate is characterized in that the curing agent contains (A) an isocyanate-terminated prepolymer obtained by reacting (a) a polyether monool of a block copolymer represented by formula (1) (wherein R is a 1-5C alkyl group; and m and n are each an integer of >=1), and having the content of the oxypropylene group larger than that of the oxyethylene group, and optionally, (b) an active hydrogen-containing aliphatic compound except the component (a), with (c) an aliphatic and/or acyclic polyisocyanate, and (B) a silane coupling agent represented by formula (2) (wherein, R is a methyl group or an ethyl group; and m is an integer of 1-5). The adhesive for the laminate is obtained by using the curing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyisocyanate curing agent for a laminate adhesive and a laminate adhesive using the same. More specifically, the present invention relates to a polyisocyanate curing agent for a laminate adhesive having a specific nonionic hydrophilic group, and a laminate adhesive using the curing agent and a polyurethane resin.

[0002]

2. Description of the Related Art Recently, composite flexible packaging has been used as a packaging method because of its strength, merchandise protection, workability at the time of packaging, advertising effect of packaging, and reduction of packaging cost by supplying a large amount of film at low cost. Is developing significantly. The adhesive used for such a film laminate is made of a resin containing an active hydrogen group such as a hydroxyl group from the viewpoint of excellent adhesive performance and durability and heat resistance, and a wide range of application to various films. Two-component curable polyurethane-based adhesives comprising a main agent and a curing agent having a polyisocyanate have become mainstream.

For example, JP-A-5-112766 describes an adhesive using a polyurethane resin and a polyisocyanate curing agent, wherein a hydrophilic polar group is introduced into the polyurethane resin. Japanese Patent Application Laid-Open No. 7-48429 describes a polyisocyanate curing agent in which a hydrophilic polar group is introduced into polyisocyanate.

[0004] However, in the polyisocyanate curing agent described in JP-A-5-112766, when a resin other than the resin used in the present invention is used as an adhesive, the adhesiveness to a metal foil, a metal-deposited film, and a polyolefin film is poor. It is enough. Also, JP-A-7-48429 discloses that
Although a water-based adhesive is described, the water-based adhesive requires a large amount of energy to scatter water.

On the other hand, use of a coupling agent for improving the adhesiveness has been studied.
No. 0272 discloses polyether polyols, polyester polyols, polyether urethane polyols,
An adhesive composition for a composite laminate comprising a polyol, which is one or more of polyester urethane polyols, an isocyanate group-containing silane coupling agent, and a polyisocyanate curing agent is disclosed.

[0006] With the recent diversification of eating habits, the level required for the performance of the laminated film has been increased. For example, there is a demand for a film which is insufficient in retort resistance and can withstand high retort. With the technique described in JP-A-63-110272, it has been difficult to obtain a laminate film satisfying the current required level.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a polyisocyanate curing agent for a laminate adhesive which is excellent in stability over time, heat resistance and durability, and particularly excellent in adhesion to metal films and polyolefin films. An object of the present invention is to provide a laminate adhesive using the same.

[0008]

That is, the present invention provides the following (1) to (3). (1) A block copolymer represented by the formula (1), wherein the polyether monool (a) has a higher oxypropylene group content than the oxyethylene group content, and an aliphatic and / or alicyclic polyisocyanate. Isocyanate group-terminated prepolymer (A) obtained by reacting (c)
And a silane coupling agent (B) represented by the formula (2):
A polyisocyanate curing agent for a laminating adhesive, comprising:

[0009]

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[0010]

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(2) a block copolymer represented by the formula (1), wherein the polyether monool (a) has a higher oxypropylene group content than the oxyethylene group content;
And an aliphatic active hydrogen group-containing compound other than (a) (b)
And an aliphatic and / or alicyclic polyisocyanate (c)
A polyisocyanate curing agent for a laminating adhesive, characterized by containing an isocyanate group-terminated prepolymer (A) obtained by reacting with a silane coupling agent (B) represented by the formula (2).

[0012]

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[0013]

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(3) A laminating adhesive characterized by using the polyisocyanate curing agent (1) or (2) and a polyurethane resin.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The isocyanate group-terminated prepolymer (A) used in the polyisocyanate curing agent for a laminate adhesive of the present invention is a block copolymer represented by the formula (1), A polyether monool (a) having an oxypropylene group content higher than the group content, and an aliphatic active hydrogen group-containing compound (b) other than (a) used as required, and an aliphatic and / or fatty acid It is obtained by reacting with a cyclic polyisocyanate (c).

[0016]

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In the case of (a), when R is a group having 6 or more carbon atoms, the adhesion of the obtained polyisocyanate curing agent to the base material tends to decrease. When the number of oxyethylene groups is larger than that of oxypropylene groups, the water resistance tends to decrease.

The preferred number average molecular weight of (a) is 800 to
It is 5,000 or more, preferably 1,000 to 3,000. When the number average molecular weight is less than the lower limit, the adhesiveness of the obtained polyisocyanate curing agent tends to decrease. Also,
If it exceeds the upper limit, the viscosity of the obtained polyisocyanate will be high, and the workability tends to be low.

(A) is obtained by a known method. First, a poly (oxyethylene) monool is produced by a ring-opening addition reaction of ethylene oxide using a monol compound as an initiator. Subsequently, it is obtained by subjecting propylene oxide to a ring-opening addition reaction.

The monol used for the initiator includes:
Examples thereof include aliphatic monoalcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, and t-butanol. Preferred in the present invention are methanol and ethanol.

In the present invention, an aliphatic active hydrogen group-containing compound (b) other than (a) is used, if necessary, in consideration of required performances such as improvement of compatibility with the base material and adhesion of different materials. be able to. (B) includes methanol, ethanol, n-propanol, i-propanol, n-
Butanol, i-butanol, t-butanol, pentanol, hexanol, heptanol, octanol,
Low molecular weight monols such as 2-ethylhexanol, benzyl alcohol, cyclohexanol and alkylene glycol monoalkyl ether; low molecular weight first monoamines such as ethylamine, butylamine and aniline; low molecular weight monoamines such as diethylamine, dibutylamine and methylaniline. 2 monoamines, active hydrogen group-containing polyester, active hydrogen group-containing polyether whose repeating unit is an oxyalkylene group having 3 or more carbon atoms, polycarbonate having an active hydrogen group, polyolefin having an active hydrogen group, hydroxy higher fatty acid having 6 or more carbon atoms And esters thereof.
Preferred in the present invention are monols.

The aliphatic and / or alicyclic polyisocyanate (c) used in the present invention is a modified aliphatic diisocyanate and / or alicyclic diisocyanate, and isocyanurate group, uretdione group, biuret group, It has one of allophanate groups.
Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tetramethyl xylylene diisocyanate, and cyclohexyl diisocyanate. These diisocyanates may be used as a mixture of two or more kinds. Further, urethane-modified, urea-modified, carbodiimide-modified, and uretonimine-modified diisocyanates can also be suitably used. Preferred (c) in the present invention is hexamethylene diisocyanate or an isocyanurate-modified polyisocyanate using hexamethylene diisocyanate.

In the present invention, an organic polyisocyanate other than (c) can be used in combination. Specifically, for example, known 2,4-tolylene diisocyanate, 2,6
-Tolylene diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, xylylene-1,2-diisocyanate, 4,4 '
-Differmethane diisocyanate, 2,4'-differmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,
4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,
Aromas such as 4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate Group diisocyanates, adduct modified products, buret modified products, carbodiimide modified products, uretonimine modified products, uretdione modified products, isocyanurate modified products and polymeric products thereof, and further, mixtures of two or more of these.

The reaction temperature in the reaction between (a) and (c) is 30 to 120 ° C., preferably 40 to 100 ° C. In addition, (b) used as needed may be made to react simultaneously with (a), or may be made to react at a different time. During the reaction, a urethanization catalyst such as dibutyltin dilaurate or triethylenediamine may be added as necessary.

In the present invention, the amount of the polyisocyanate (a) introduced is determined by the mass ratio of (a) to (c).
(A) :( c) = 1: 100-80: 100, preferably (a) :( c) = 1.5: 100-70: 100. When (b) is used, the preferred amount of (b) to be introduced is (b):
(C) = 1: 100-80: 100, preferably (b) :( c) = 1: 100-70: 100.

When the amount of (a) introduced is less than the lower limit, the adhesiveness tends to decrease. On the other hand, when the ratio exceeds the upper limit, the isocyanate group content is reduced as a result, so that the adhesive strength tends to be reduced.

The average number of functional groups of the isocyanate group-terminated prepolymer (A) in the present invention is 2 to 5, preferably 2.1 to 4.9. If the average number of functional groups is too low, the strength and durability of the cured product are likely to decrease. If the average number of functional groups is too high, the crosslink density of the adhesive layer becomes too high, and the cured product tends to become brittle.

The isocyanate group-terminated prepolymer (A) in the present invention has an isocyanate group content of 10 to 20.
%, Preferably 10.5 to 19.5% by mass.
If the isocyanate group content is too small, the crosslinked density is low, and the strength and durability of the cured product are likely to decrease. If the isocyanate group content is too large, (A)
In this case, since the amount of (a) introduced is reduced, the adhesiveness tends to decrease.

The free diisocyanate content of the isocyanate group-terminated prepolymer (A) in the present invention is 1
%, Preferably 0.9% or less. If the free diisocyanate content is too high, the pot life after dispersion in water is shortened, and the problem of odor tends to occur.

The silane coupling agent (B) used in the present invention is represented by the formula (2).

[0031]

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It is well known that the use of a silane coupling agent improves the adhesiveness, heat resistance, chemical resistance and the like of an adhesive. However, if a silane coupling agent is previously added to a main component, particularly a main component having a functional group such as an amino group or an epoxy group, coloring or thickening may occur over time. This is presumably because the functional group in the main agent reacts with the alkoxysilane portion of the silane coupling agent. In addition, since the silane coupling agent usually has a functional group such as an amino group and an epoxy group, if the polyisocyanate curing agent and the silane coupling agent are blended, the isocyanate group in the curing agent is similarly The functional groups in the silane coupling agent may react and cause an increase in viscosity over time.

Therefore, for the stability of the laminating adhesive over time, it is sufficient to store each component and mix each component immediately before use. However, it takes time to store and mix each component, and there has been a demand for a laminate adhesive as at least two components. If a silane coupling agent is not used, it naturally becomes a two-component system, but in order to obtain a laminated film for high retort, the adhesiveness is insufficient.
Therefore, a silane coupling agent is required for the high retort laminating adhesive.

The functional groups of the silane coupling agent (B) used in the present invention are -NCO and Si-OR (R is a methyl group or an ethyl group). It does not react with the prepolymer. Therefore, the polyisocyanate curing agent of the present invention has good temporal stability.

The polyisocyanate curing agent of the present invention may contain, if necessary, pigments, dyes, dispersion stabilizers, viscosity regulators, leveling agents, gelling inhibitors, light stabilizers, antioxidants, ultraviolet absorbers. Agents, heat resistance improvers, inorganic and organic fillers, plasticizers, lubricants, antistatic agents, reinforcing materials, catalysts, thixotropic agents and the like can be added.

The so-called main agent in the laminate adhesive of the present invention is not particularly limited as long as it has an active hydrogen group. Examples thereof include polyurethane resins, polyester resins, polyamide resins, and acrylic resins. resin,
Coumarone-based resins, melamine-based resins, urea-based resins, rosin-based resins, epoxy-based resins, phenolic resins, vinyl acetate-based resins, cellulose-based resins, natural resins such as starch and glue, polyvinyl alcohol, etc. . The number average molecular weight of the resin used for the main agent is 500 to 1
00,000, preferably 1,000 to 80,000. Among these, polyurethane-based resins are preferable in consideration of adhesion to a substrate, durability, and the like.

The polyurethane resin suitably used in the present invention includes a polyurethane urea resin having a urethane bond and a urea bond in addition to a polyurethane resin having a urethane bond.

In the molecule of the polyurethane resin, 1
And more preferably two or more active hydrogen groups such as hydroxyl groups. A polyisocyanate curing agent for a laminating adhesive having a hydrophilic polar group is added to these polyurethane resins to be used as a two-component curable laminating adhesive.

The polyurethane resin is obtained by reacting an active hydrogen group-containing compound with an organic polyisocyanate.

The active hydrogen group-containing compound is what is called a long-chain polyol and / or a chain extender. The polyurethane resin suitable for the present invention preferably contains a long-chain polyol in an amount of 50 to 90% by mass.

Examples of the long-chain polyol include polyester polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, animal and vegetable oil-based polyols, and copolyols thereof. These long-chain polyols may be used alone or in combination of two or more. The number average molecular weight of these long-chain polyols is preferably from 500 to 10,000. In the present invention, polyester polyol is preferred in consideration of adhesiveness, durability and the like.

Examples of the polyester polyol include known succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid,
Hexahydroorthophthalic acid, naphthalenedicarboxylic acid, polycarboxylic acids such as trimellitic acid, acid esters,
Or one or more acid anhydrides and the like, ethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5- Pentanediol, neopentyl glycol, 1,8-octanediol,
1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, or an ethylene oxide or propylene oxide adduct of bisphenol A, low molecular weight polyols such as glycerin, trimethylolpropane, and pentaerythritol; hexamethylenediamine , Xylylenediamine, low-molecular-weight polyamines such as isophoronediamine, monoethanolamine, obtained by a dehydration condensation reaction with at least one kind of low-molecular-weight amino alcohols such as diethanolamine,
Polyester polyol or polyester amide polyol is mentioned. In the present invention, the “low molecular weight” in the low molecular weight polyol, low molecular weight polyamine and low molecular weight amino alcohol is one having a number average molecular weight of less than 500. Further, the low-molecular polyol is used as an initiator,
Lactone-based polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone.

Examples of the polycarbonate polyol include those obtained by a dealcoholation reaction, a phenol removal reaction or the like of the low-molecular polyol described above with diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate or the like.

Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc. obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc., and polyether polyols obtained by copolymerizing them. Examples include polyester ether polyols using polyester polyols and polycarbonate polyols as initiators.

Examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene.

The animal and vegetable oil-based polyols include dehydrated castor oil-based polyols, castor oil-based polyols, and silk fibroin.

Further, the number average molecular weight is 500 to 10,000.
So long as it has two or more active hydrogen groups, besides dimer acid polyol, hydrogenated dimer acid polyol, polyester resin, polyamide resin, acrylic resin, cumarone resin, melamine resin, urea Resin, rosin resin, epoxy resin, phenol resin,
Cellulosic resins such as cellulose, natural resins such as starch and glue, and resins such as polyvinyl alcohol can also be suitably used as long-chain polyols.

The chain extender generally has a number average molecular weight of 500
A compound containing two or more active hydrogen groups in less than one molecule, and the above-mentioned low-molecular polyol, low-molecular polyamine,
Examples thereof include low molecular weight amino alcohols, and these can be used alone or in combination of two or more.

Examples of the organic polyisocyanate include the organic diisocyanate used in the above-mentioned curing agent for a laminating adhesive and a modified product thereof.

The isocyanate group / active hydrogen group (molar ratio) of the active hydrogen compound and the organic polyisocyanate in the synthesis of the polyurethane resin is preferably 0.6 / 1 to 1 / 0.6. When synthesizing a polyurethane resin, the conditions under which gelation does not occur are determined based on the average number of isocyanate groups of the organic polyisocyanate and the average number of active hydrogen groups of the active hydrogen compound, and each raw material is blended to satisfy this condition. It is important to. The compounding ratio is described in J. P.
According to the gelation theory theoretically calculated by Flory, Khun et al., In practice, the active hydrogen compound and the organic polyisocyanate are reacted at a compounding ratio taking into account the reactivity ratio of the reactive group contained in each molecule. Thereby, the polyurethane resin can be produced without gelation. The polyurethane resin to be synthesized contains an active hydrogen group or an isocyanate group, and has a number average molecular weight of 800 to 100,
000, particularly preferably 1,000 to 80,000. If the number average molecular weight is too large, the resin viscosity will be high and workability will be poor. If the number average molecular weight is too small, the bonding strength will be insufficient.

In the production of the polyurethane resin in the present invention, a conventionally known method, that is, a solution reaction method in which the raw materials are dissolved in an organic solvent and reacted, or the respective raw materials are sufficiently mixed and reacted without a solvent. A solventless reaction method or the like can be used. Also, a one-shot method in which an active hydrogen group-containing compound and an organic polyisocyanate are reacted at once, or an active hydrogen compound and an organic diisocyanate are reacted with an isocyanate group in excess to synthesize an isocyanate group-terminated prepolymer, and then the active It can be synthesized by a known method such as a prepolymer method for reacting a hydrogen compound.

In the case of the one-shot method, the ratio of isocyanate group / active hydrogen group is from 0.5 to 2, preferably
0.8 to 1.5. When it is less than 0.5, the molecular weight of the polyurethane resin is too small, so that the durability is lacking. In the case of two or more, when synthesizing the resin, many isocyanates which do not participate in the reaction are present.

In the case of the prepolymer method, the ratio of isocyanate group / active hydrogen group at the time of prepolymer synthesis is 1.1 to 5.
0, and preferably 1.5 to 4.0. If it is less than 1.1, the molecular weight of the prepolymer becomes too large, making it difficult to proceed to the subsequent reaction step. If it exceeds 5.0, the adhesiveness will be poor.

Examples of the active hydrogen compound to be reacted after the synthesis of the isocyanate group-terminated prepolymer include the aforementioned polyols, polyamines and amino alcohols.
If necessary, a terminal blocking agent such as monoamines such as ethylamine, diethylamine and aniline and monools such as methanol and ethanol may be partially used.

When synthesizing the isocyanate group-terminated prepolymer or polyurethane resin used in the present invention,
Additives commonly used in the production of polyurethane resins such as catalysts and stabilizers can be used. Examples of such a catalyst include tertiary amines such as triethylamine and triethylenediamine, metal salts such as potassium acetate and zinc stearate, and organic metal compounds such as dibutyltin laurate and dibutyltin oxide. Examples of the stabilizer include a stabilizer against ultraviolet rays such as substituted benzotriazoles and a stabilizer against thermal oxidation such as phenol derivatives. The reaction temperature at the time of urethanization is 10 to 120.
° C, preferably 30 to 100 ° C.

The curing agent for a laminating adhesive and the laminating adhesive of the present invention may optionally contain additives and auxiliaries commonly used in adhesives. For example, pigments, dyes, coupling agents, anti-blocking agents, dispersion stabilizers, viscosity modifiers, leveling agents, anti-gelling agents, light stabilizers, antioxidants, ultraviolet absorbers, heat resistance improvers, plasticizers, Antistatic agents, reinforcing materials, catalysts, thixotropic agents, antibacterial agents, fungicides, lubricants, inorganic and organic fillers and the like. As a compounding method, a known method such as stirring and dispersion is used.

In the present invention, an organic solvent may be used for adjusting viscosity and improving wettability. Examples of the organic solvent include toluene, xylene, swazol (an aromatic hydrocarbon solvent manufactured by Cosmo Oil Co., Ltd.) and solvesso (an aromatic hydrocarbon solvent manufactured by Exxon Chemical Co., Ltd.)
Aromatic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone, alcohol solvents such as methanol, ethanol and isopropanol, ester solvents such as ethyl acetate, butyl acetate and isobutyl acetate, and ethylene glycol. Glycol ether ester solvents such as ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, and ethyl-3-ethoxypropionate; tetrahydrofuran;
Examples include ether solvents such as dioxane. One or more of the above solvents can be used.

The mixing ratio of the polyurethane resin and the curing agent for the laminating adhesive is expressed by mass ratio: polyurethane resin / curing agent for the laminating adhesive = 100/1 to 100/200
It is particularly preferable that the curing agent for the polyurethane resin / laminate adhesive is 100/5 to 100/180.
If the amount of the curing agent for the laminating adhesive is too small, the durability of the crosslinked resin becomes insufficient. If the amount is too large, the crosslinked resin becomes inadequate in flexibility and becomes unsuitable.

In the laminate adhesive of the present invention, other resins than the above-mentioned polyurethane resins may be used, if necessary. Other resins include, but are not limited to, polyurethane resins, polyamide resins, polyester resins, acrylic resins, epoxy resins, polyvinyl chloride resins, ethylene-vinyl acetate resins, nitrile resins, cellulose resins such as nitrocellulose, and petroleum resins. Resins.

The laminate adhesive of the present invention is excellent in adhesiveness to various substrates, durability, etc., and is therefore used for film lamination, plywood, furniture, automobiles, railways, electric appliances, non-woven fabrics, shoes, and bags. It can be used in various fields such as adhesives, and is particularly useful as a laminate adhesive. Furthermore, since it has good adhesion to metals and polyolefins, it is useful as a laminating adhesive using a metal foil, a metal-deposited film, or a polyolefin film.

Examples of the film as a substrate constituting the laminate film include stretched polypropylene, unstretched polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthylate, polybutylene naphthylate, nylon, low density polyethylene,
Medium density polyethylene, high density polyethylene, ethylene-
Polymer films such as vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, vinyl chloride, polyvinyl alcohol, polystyrene, polycarbonate, polyvinylidene chloride, cellophane, metal foils such as aluminum and copper, and these metals Film deposited on molecular film,
Paper and polymer-coated films thereof.

The polymer film is preferably subjected to a surface treatment such as a corona discharge treatment in order to improve the adhesive strength. Further, it is necessary to consider the type, amount, and surface characteristics of the polymer to be coated on the polymer coating film.

As a laminating method using the laminating adhesive of the present invention, methods such as wet lamination, dry lamination, hot melt lamination, extrusion lamination and non-solvent lamination can be applied.

The amount of the adhesive applied in the application step is 0.5 to 10 g / m ² , preferably 1 to 8 g / m ² in terms of resin. If the coating amount is outside this range, the adhesive strength tends to be insufficient.

After the adhesive is applied to the film, it is dried if necessary and bonded. Thereafter, if necessary, pressure or heat is applied to accelerate the curing reaction. A preferable pressure at this time is 0.01 to 2 MPa, and a preferable temperature is 40 to 150 ° C.

According to such a method, not only a laminate of two films but also a laminate of three or more films can be manufactured.

[0067]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention should not be construed as being limited to only the examples. Note that “%” in Synthesis Examples, Examples and Comparative Examples indicates “% by mass” unless otherwise specified.

[Synthesis of Curing Agent for Laminating Adhesive] Example 1 Coronate (registered trademark) manufactured by Nippon Polyurethane Industry Co., Ltd. was placed in a reactor having a capacity of 2 L, comprising a stirrer, a thermometer, an Aline cooling tube, and a nitrogen gas inlet tube. 601 g of HX and 399 g of monol (1) were charged and reacted at 70 ° C. for 3 hours. Thereafter, 1 g of the coupling agent (1) was charged to obtain a polyisocyanate curing agent A for a laminate adhesive.
The viscosity at 25 ° C. of the polyisocyanate curing agent A is 2,720 mPa · s, and the isocyanate group content is 11.
1%. Further, when the polyisocyanate curing agent A was stored at 25 ° C. for one month in a dark place and the stability with time was observed, no particular change in appearance could be confirmed.

Examples 2 to 6, Comparative Examples 1 and 2 Polyisocyanate curing agents B to H for a laminate adhesive were obtained in the same manner as in Example 1 using the raw materials shown in Table 1.
In addition, the obtained polyisocyanate curing agent was used in a dark place.
After storage at 5 ° C. for one month, the stability with time was observed. Table 1 shows the results
Shown in

[0070]

[Table 1]

In Examples 1 to 6, Comparative Examples 1 and 2 and Table 1, coronate HX: isocyanurate-modified polyisocyanate of hexamethylene diisocyanate Isocyanate content = 21.3% Viscosity at 25 ° C. = 1,500 mPa · s monool ( 1): Propylene oxide added to methoxy polyethylene glycol having a number average molecular weight of 400. Total number average molecular weight = 1,100. Monool (2): Propylene oxide added to methoxy polyethylene glycol having a number average molecular weight of 400. Total number average molecular weight = 1,400 monool (3): Methoxy polyethylene glycol having a number average molecular weight of 700 with propylene oxide added Total overall number average molecular weight = 1,700 Monool (4): methoxy Polyethylene grease Number of total molecular weight of coal = 400 Monool (5): Ricinoleic acid methyl ester Coupling agent (1): γ-isocyanatopropyltrimethoxysilane Coupling agent (2): γ-isocyanatopropyltriethoxysilane coupling Agent (3): γ-aminopropyltrimethoxysilane Stability over time ：: No change in appearance is observed (solidification, generation of precipitates or suspended matter is not observed) ×: Change in appearance is observed (solidification, precipitate) And the generation of suspended matter is recognized)

As shown in Table 1, the polyisocyanate curing agent of the present invention showed good storage stability. On the other hand, a polyisocyanate curing agent H to which an amino group-containing coupling agent is added
Was poor in stability over time.

[Synthesis of Polyurethane Resin for Main Agent] In the same apparatus as in Synthesis Example 1, 246 g of polyol A
And 200 g of ethyl acetate were charged and dissolved at 30 ° C. Next, 41 g of TDI and 0.03 of DOTDL
g, and reacted at 80 ° C. for 4 hours. Since the viscosity increased as the urethanization reaction progressed, ethyl acetate was added in several portions. When the peak of the isocyanate group in the infrared absorption analysis disappeared, 350 g of ethyl acetate was further added.
To obtain a polyurethane resin having a solid content of 50%.

In the synthesis examples, polyol A: ethylene glycol / neopentyl glycol = 1/1, adipic acid / isophthalic acid = 1/1
Polyester diol obtained from each (molar ratio) Number average molecular weight = 2,000 NPG: neopentyl glycol TDI: 2,4-tolylene diisocyanate DOTDL: dioctyltin dilaurate

(Adhesive blending) The polyurethane resin and the polyisocyanate curing agent were blended in a solid content conversion ratio of polyurethane resin / polyisocyanate curing agent = 100/5 (mass ratio). 1-8 were obtained.

(Measurement of Adhesive Strength) Example 7 AD-1, corona-treated PET film (film thickness: 1)
2μ), aluminum foil (film thickness: 7μ), corona treated C
A PP film (film thickness: 70 μ) was set in a dry laminator. AD-1 was applied by a gravure roll onto the corona-treated surface of the corona-treated PET film so that the application amount was 3.5 g / m ² in a dry state. After applying the adhesive, it was passed through a drying oven set at 80 ° C.
The laminate was bonded to an aluminum foil with a bonding roll of ℃ × 0.3 MPa. Next, AD-1 was applied to the aluminum foil surface with a gravure roll so that the applied amount was 3.5 g / m ² in a dry state. After the adhesive was applied, it was passed through a drying oven set at 80 ° C., and then bonded to a corona-treated surface of a corona-treated CPP with a bonding roll of 100 ° C. × 0.3 MPa. The film speed is 50 m / min. After lamination, curing was performed at 40 ° C. for 3 days to obtain a laminate film A. Laminate film A as it is 15mm
The sheet was cut into a width, and a T-type peel test was performed at a tensile speed of 300 mm / min and a measurement atmosphere of 25 ° C. × 50% RH.
In addition, the laminated film A is
After heat-sealing the three sides under the condition of 80 ° C. × 0.3 MPa × 1 second to form a bag, ketchup / salad oil /
A mixed solution of vinegar = 1/1/1 (mass ratio) was added, and heat-sealed and sealed under the above conditions. After high retort at 135 ° C. for 20 minutes, T-peel test (sample width: 1)
5 mm, tensile speed: 300 mm / min, measurement atmosphere: 25
C. x 50% RH).

Examples 8 to 12 and Comparative Examples 3 and 4 AD-2 to 8 were also prepared in the same manner as in Example 1 by preparing laminated films and conducting tests. Table 2 shows the test results of Examples 7 to 12 and Comparative Examples 3 and 4.

[0078]

[Table 2]

In Examples 1 to 6, Comparative Examples 1 and 2 and Table 2, PET: polyethylene terephthalate Al: aluminum foil CPP: undrawn polypropylene PETf: PET material break Alf: Al material break

The laminating adhesive using the polyisocyanate curing agent of the present invention showed good adhesiveness, but AD-7, which did not use a coupling agent, had a reduced adhesive strength after high retort.

[0081]

As described above, the polyisocyanate curing agent of the present invention exhibited good stability over time. Also,
In particular, it has become possible to provide a laminate adhesive having excellent adhesion and durability to a metal base material.

Continued on the front page F term (reference) 4J040 EF111 EF141 EF151 EF161 EF181 EF201 EF261 EF271 EF281 HD36 JA02 JB02 KA16 LA05 LA06 LA08 MA02 MA11 NA08

Claims (3)

[Claims] 1. A block copolymer represented by the formula (1), wherein the polyether monool (a) has a higher oxypropylene group content than the oxyethylene group content, and an aliphatic and / or alicyclic A polyisocyanate-terminated prepolymer (A) obtained by reacting with a polyisocyanate (c), and a silane coupling agent (B) represented by the formula (2): Isocyanate curing agent. Embedded image Embedded image 2. A block copolymer represented by the formula (1), wherein the polyether monool (a) has a higher oxypropylene group content than the oxyethylene group content, and an aliphatic system other than (a). An active hydrogen group-containing compound (b);
It is characterized by containing an isocyanate group-terminated prepolymer (A) obtained by reacting with an aliphatic and / or alicyclic polyisocyanate (c), and a silane coupling agent (B) represented by the formula (2). A polyisocyanate curing agent for a laminate adhesive. Embedded image Embedded image 3. A laminate adhesive comprising the polyisocyanate curing agent according to claim 1 and a polyurethane resin.