JP6171467B2 - Two-component adhesive composition for laminating - Google Patents

Description

  The present invention relates to an adhesive composition and a laminating method. More specifically, laminating various plastic films, metal vapor-deposited films, aluminum foils, etc., and laminating two-component mixed adhesive composition for use in producing composite films mainly used for packaging materials such as foods, pharmaceuticals, and detergents. Related to things.

  Dry lamination is a technique in which an adhesive is applied to one material surface, then the solvent is evaporated to dryness, and the other material is laminated while being heated and pressed. This technology is widely used in the manufacture of food packaging materials that require high performance because any film can be bonded together freely and a composite film having performance according to the purpose can be obtained. Yes.

  Conventionally, a two-component reaction type polyurethane adhesive has been mainly used as an adhesive for dry lamination. A two-component reactive adhesive consists of a main component having a hydroxyl group at the polymer end (polyol component) and a curing agent having an isocyanate group (polyisocyanate component), and forms a urethane bond by the reaction between the hydroxyl group and the isocyanate group. To do.

A laminate adhesive for flexible packaging materials is also one of the typical uses of the polyurethane resin. A laminating adhesive undergoes a curing reaction even at room temperature, but takes a long time to be completely cured. Therefore, a process for promoting the reaction in an aging room at about 40 to 50 ° C. is essential.
In order to improve productivity by shortening the aging process, the adhesive product contains a catalyst for urethane reaction. As typical catalysts, organotin catalysts exhibiting excellent activity, mainly dibutyltin dilaurate (DBTDL) or octyltin maleate are widely used.

However, in recent years, toxicity problems have been pointed out with organotin catalysts. In particular, tributyltin contained as an impurity in DBTDL has become a problem of toxicity to the human body as an environmental hormone. Already there has been a movement to regulate organotin catalysts in polyurethane production, mainly in Europe, and there is a strong demand for alternative catalysts for organotin catalysts.
Since the laminating adhesive for soft wrapping materials occupies the majority of food applications, regulations on organotin catalysts are particularly strict compared to other urethane products, and various catalysts have been studied as alternatives to organotin.

  Examples thereof include metal complex catalysts such as iron, zinc, and titanium, inorganic metal catalysts, and tertiary amines (see, for example, Patent Document 1). However, the activity is greatly inferior to that of organotin, and if the content is increased in order to improve the activity, the appearance, pot life, adhesive properties and the like are adversely affected. In addition, most of the above-mentioned alternative catalysts are not listed on the positive list of the most stringent European food packaging laws and regulations in the world. There is a possibility of exceeding.

JP 2003-82052 A

  An object of the present invention is a urethane obtained by using a catalyst that is equivalent to or more than tin resin or urethane resin adhesive using an alternative catalyst and that can meet the legal regulations of food packaging. It is providing the adhesive composition which uses a system resin as an essential component.

  As a result of intensive studies to solve the above problems, the present inventor has found that a urethane resin obtained by using a specific cyclic amide compound as the catalyst solves the above problems, and has completed the present invention.

  That is, the present invention provides an adhesive composition comprising a polyol resin (A), a polyisocyanate (B), and a cyclic amide compound (C).

  According to the present invention, it is possible to provide an adhesive composition having excellent curing speed and stable pot life without using legally regulated raw materials.

  Examples of the polyol resin (A) used in the present invention include polyol (a1) described later, or those obtained by reacting polyol (a1) with polycarboxylic acids described later.

  Examples of the polyol (a1) include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexane Diglycol such as diol, 1,4-cyclohexanedimethanol, triethylene glycol, polycaprolactone diol, dimer diol, bisphenol A, hydrogenated bisphenol A, etc. , Polyesters obtained by ring-opening polymerization reaction of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, ethylene glycol, diethylene glycol, triethylene Ethylene oxide starting with compounds having two active hydrogen atoms such as glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol And polyethers obtained by addition polymerization of monomers such as propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene.

Examples of the polycarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid. Acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p , P'-dicarboxylic acids and anhydrides or ester-forming derivatives of these dicarboxylic acids; p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, ester-forming derivatives of these dihydroxycarboxylic acids, dimer acids, etc. Of the polybasic acids.

  Examples of the polyisocyanate (B) include organic compounds having at least two isocyanate groups in the molecule. Examples of the organic polyisocyanate compound include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), lysine diisocyanate, trimethylhexamethylene diisocyanate, Polyisocyanates such as 1,3- (isocyanatomethyl) cyclohexane, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate; adducts of these polyisocyanates, burettes of these polyisocyanates, or these polyisocyanates And polyisocyanate derivatives (modified products) such as isocyanurates.

The equivalent ratio [(B) / (A)] of the hydroxyl group equivalent of the polyol resin (A) and the isocyanate equivalent of the polyisocyanate (B) is preferably 0.5 to 5.0.

  Examples of the cyclic amide compound (C) used in the present invention include δ-valerolactam, ε-caprolactam, ω-enanthollactam, η-capryllactam, β-propiolactam, and the like among these. Caprolactam is preferred.

Further, an existing catalyst such as dibutyltin dilaurate (DBTDL), tetraisopropoxytitanium (Ti (acac) ₄ ), triethylenediamine (DABCO) may be used in combination as long as the effects of the present invention are not impaired.

  The cyclic amide compound (C) is preferably 0.1 to 5 parts by weight per 100 parts by weight in total of the polyol resin (A) and the polyisocyanate (B).

  The composition of this invention may use a pigment together as needed. In this case, usable pigments are not particularly limited. For example, extender pigments, white pigments, black pigments, gray pigments, red pigments described in the Paint Material Handbook 1970 edition (edited by the Japan Paint Industry Association) Examples thereof include organic pigments and inorganic pigments such as pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearl pigments, and plastic pigments. Specific examples of these colorants include various types, and examples of organic pigments include various insoluble azo pigments such as Bench Gin Yellow, Hansa Yellow, Raked 4R, etc .; Soluble properties such as Raked C, Carmine 6B, Bordeaux 10 and the like. Azo pigments;

Various (copper) phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; various chlorine dyeing lakes such as rhodamine lake and methyl violet lake; various mordant dye pigments such as quinoline lake and fast sky blue; anthraquinone pigment; Various vat dyes such as thioindigo pigments and perinone pigments; various quinacridone pigments such as Cincacia Red B; various dioxazine pigments such as dioxazine violet; various condensed azo pigments such as chromoftal; aniline Black etc. are mentioned.

  Examples of inorganic pigments include various chromates such as chrome lead, zinc chromate, and molybdate orange; various ferrocyan compounds such as bitumen; titanium oxide, zinc white, mapico yellow, iron oxide, bengara, chrome oxide Various metal oxides such as green and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red and mercury sulfide;

Various sulfates such as barium sulfate and lead sulfate; Various silicates such as calcium silicate and ultramarine blue; Various carbonates such as calcium carbonate and magnesium carbonate; Various phosphates such as cobalt violet and manganese purple; Aluminum Various metal powder pigments such as powder, gold powder, silver powder, copper powder, bronze powder and brass powder; flake pigments of these metals, mica flake pigments; mica flake pigments coated with metal oxides, mica-like iron oxide Examples thereof include metallic pigments such as pigments and pearl pigments; graphite and carbon black.

  Examples of extender pigments include precipitated barium sulfate, powder, precipitated calcium carbonate, calcium bicarbonate, cryolite, alumina white, silica, hydrous finely divided silica (white carbon), ultrafine anhydrous silica (Aerosil), and silica sand (silica). Sand), talc, precipitated magnesium carbonate, bentonite, clay, kaolin, ocher and the like.

  Furthermore, examples of the plastic pigment include DIC Corporation Grandol PP-1000, PP-2000S, and the like.

  As the pigment used in the present invention, since it is excellent in durability, weather resistance and design, inorganic oxides such as titanium oxide and zinc white as a white pigment, and carbon black as a black pigment are more preferable.

  The weight ratio of the pigment used in the present invention is preferably 1 to 400 parts by weight, more preferably 10 to 300 parts by weight, with respect to 100 parts by weight of the resin component, because it is excellent in adhesiveness and blocking resistance.

  If necessary, the adhesive composition of the present invention may contain other additives other than those described above. Examples of the additive include additives generally used in resin compositions that form films and coating films. Examples of additives include leveling agents; inorganic fine particles such as colloidal silica and alumina sol; organic fine particles based on polymethyl methacrylate; antifoaming agents; anti-sagging agents; wetting and dispersing agents; silane coupling agents; Ultraviolet absorber; Metal deactivator; Peroxide decomposing agent; Flame retardant; Reinforcing agent; Plasticizer; Lubricant; Rust inhibitor; Fluorescent brightener; Inorganic heat absorber; Agents; dehydrating agents; and the like.

  The adhesive composition of the present invention can be usually prepared by preparing a main component premix in which components other than the polyisocyanate compound, which is a curing agent, are blended in advance, and mixing this with a polyisocyanate compound. .

  In the laminating method of the present invention, the adhesive composition is applied to a substrate with a gravure coater, a die coater or a lip coater, and dried and bonded to another substrate. In the die coater and the lip coater, the coating width can be freely adjusted by deckles attached to both ends of the die or the lip portion. When a volatile acidic compound is used, the adhesive gels when the acidic compound volatilizes, so the pH must always be maintained at 1-8, preferably 3-7.

The coating amount of the adhesive is about 0.5 to 6.0 g / m ² , preferably 1.0 to 4.0 g / m ² .

  When the adhesive composition of the present invention is used, the adhesive is cured in 6 to 24 hours at room temperature or under heating after lamination, and expresses practical physical properties.

  Hereinafter, the contents and effects of the present invention will be described in more detail with reference to examples. In the examples, “parts” means “parts by weight”.

Synthesis Example Preparation Example of Polyol Solution In a polyester reaction vessel equipped with a stirrer, thermometer, nitrogen gas introduction tube, rectification tube, moisture separator, etc., 41.2 parts of isophthalic acid, 18.0 parts of adipic acid, sebatin 9.8 parts of acid, 17.3 parts of ethylene glycol, 14.9 parts of neopentyl glycol, 16.7 parts of 1,6-hexanediol and 0.006 part of titanium catalyst were charged, and the temperature at the top of the rectification tube Was gradually heated so as not to exceed 100 ° C., and the internal temperature was maintained at 240 ° C. When the acid value reached 5 mgKOH / g, xylene was added and xylene was refluxed at the same temperature using a water separator, and the reaction was further continued until the acid value became 2 mgKOH / g or less. The pressure was reduced to 10 mmHg or less and held for 1.5 hours to complete the esterification reaction, and an intermediate polyester polyol having a hydroxyl value of 28 was obtained. Next, 70 parts of ethyl acetate, 3.1 parts of isophorone diisocyanate, and 0.05 parts of DBTDL are added to 100 parts of the obtained intermediate polyester polyol, and the mixture is heated and stirred at 80 ° C. for 30 minutes. Got.

Example 1
As shown in Table 1, 100 parts of polyol resin solution A, 10 parts of polyisocyanate solution B (KW-75 manufactured by DIC Corporation), 0.60 part of δ-valerolactam and 160 parts of ethyl acetate were blended.

Example 2
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.30 part of ε-caprolactam.

Example 3
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.60 part of ε-caprolactam.

Example 4
The same procedure was carried out except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.20 parts of ε-caprolactam.

Example 5
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.80 parts of ε-caprolactam.

Example 6
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.60 part of ω-enanthol lactam.

Example 7
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.60 part of η-capryllactam.

Example 8
The compounding was performed in the same manner except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.60 part of β-propiolactam.

Comparative Example 1
The same procedure was carried out except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.80 parts of pyrrolidone.

Comparative Example 2
The same procedure was followed except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.80 parts of N-methyl-epsilon-caprolactam.

Comparative Example 3
The same procedure was carried out except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.01 part of DBTDL.

Comparative Example 4
The compounding was conducted in the same manner except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.06 part of DBTDL.

Comparative Example 5
The compounding was conducted in the same manner except that 0.60 part of δ-valerolactam of Example 1 was changed to 0.18 part of DBTDL.

Comparative Example 6
The compounding was conducted in the same manner except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.80 parts of tetraisopropoxytitanium (Ti (acac) 4).

Comparative Example 7
The same procedure was carried out except that 0.60 part of δ-valerolactam of Example 1 was changed to 1.80 parts of TEDA.

  The curing rate, heat seal strength, and pot life were measured by the methods described below for the adhesives obtained in the respective Examples and Comparative Examples. The obtained results are shown in Table 1.

[Curing speed]
After blending the above main agent, curing agent, catalyst, and solvent, this blended solution is coated on a film so that the coating amount is about 2.5 to 3.5 g / m 2 in solid content, dried with a dryer, and then a calender roll. Thus, a laminate film was prepared by closely adhering the coated surface of this film to another sealant film and the coated surface.
The laminate film was prepared in two configurations: OPP (biaxially stretched polypropylene film) / CPP (unstretched polypropylene film) and ONY (biaxially stretched nylon film) / LLDPE (linear / low density polyethylene film).
This laminate film was placed in a constant temperature bath at 40 ° C., and measured according to the evaluation test method shown below every time.
1) Measurement of isocyanate reaction rate Evaluation by measuring infrared absorption spectrum of OPP / CPP laminate film by transmission method and measuring absorption spectrum derived from isocyanate (near 2270 cm ^-1 ) ◎: Isocyanate reaction rate is 90% after 6 hours Evaluation ◎: Isocyanate reaction rate is 70% or more after 6 hours Evaluation: Isocyanate reaction rate is 50% or more after 6 hours Evaluation: Isocyanate reaction rate is less than 50% after 6 hours

Heat seal strength measurement The ONY / LLDPE laminate film was folded so that the sealant was inside, and the folded portion was heat sealed at 1 atm, 180 ° C. for 1 second. This was cut into a strip shape so as to have a width of 15 mm, and the strength of the heat seal part was measured at a peeling rate of 300 mm / min using a peeling tester.
Evaluation ◎: Evaluation that film break occurs after 3 hours ○: Evaluation that film break occurs after 6 hours Δ: Evaluation that edge break occurs after 6 hours ×: Triangular separation occurs after 6 hours

[Pot life]
The above-mentioned main agent, curing agent, catalyst, and solvent were blended to prepare a blended liquid with a solid content of 30%. This was allowed to stand at 25 ° C. for 30 minutes, and then the viscosity was measured with Zahn cup # 3.
The mixture was placed in a constant temperature bath at 40 ° C. and the reaction was promoted for 6 hours. After standing at 25 ° C. for 30 minutes, the viscosity was measured again.
Further, the mixture was allowed to stand at room temperature, and the viscosity was measured 18 hours later (24 hours after the blending).
Evaluation ◎: The viscosity of the liquid mixture after 24 hours is less than 20 seconds Evaluation ○: The viscosity of the liquid mixture after 24 hours is less than 25 seconds Evaluation Δ: The viscosity of the liquid mixture after 24 hours is less than 30 seconds Evaluation x: 24 hours The viscosity of the later compounding liquid is 30 seconds or more

Claims (5)

0.1 to 5 parts by weight of δ-valerolactam, ε-caprolactam per 100 parts by weight of polyol resin (A) and polyisocyanate (B), and the total of the polyol resin (A) and polyisocyanate (B), Two-component mixed adhesive for laminating comprising one or more cyclic amide compounds (C) selected from the group consisting of ω-enanthol lactam, η-capryl lactam, and β-propiolactam Composition. The two-component liquid for laminating according to claim 1, wherein the content of the cyclic amide compound (C) is 0.1 to 1.8 parts by weight per 100 parts by weight in total of the polyol resin (A) and the polyisocyanate (B). Mixed adhesive composition. The laminate according to claim 1 or 2, wherein the content of the cyclic amide compound (C) is 0.3 to 1.8 parts by weight per 100 parts by weight in total of the polyol resin (A) and the polyisocyanate (B). Two-component mixed adhesive composition. The two-component mixed adhesive composition for laminate according to claim 1, wherein the cyclic amide compound (C) is ε-caprolactam. A laminated film in which a cured film of the two-component mixed adhesive composition for laminating according to claim 1 is laminated on a plastic film.