JP2009073949A - Adhesive composition - Google Patents

Abstract

The present invention provides an adhesive composition that exhibits excellent initial adhesiveness, normal adhesive strength, and heat resistance with respect to a hardly adhesive polyolefin-based film.
An adhesive composition comprising (A) a hydroxyl group-containing thermoplastic polyester urethane resin, (B) a solvent, (C) an amine-modified urethane resin, and (D) a polyisocyanate compound.
[Selection figure] None

Description

  The present invention relates to an adhesive composition, and more particularly to an adhesive composition suitable mainly as a two-pack adhesive composition for vinyl chloride films and polyolefin films, and more specifically, an amine-modified urethane resin. The present invention relates to an adhesive composition that exhibits excellent initial adhesiveness, normal adhesive strength, and heat resistance even in the case of a polyolefin film having low polarity, strong crystallinity, and poor adhesion.

A two-component mixed solvent adhesive consisting of a base material in which a thermoplastic polyester urethane resin is dissolved in a solvent and a polyisocyanate curing agent is excellent in normal adhesive strength and heat resistance. Widely used for bonding materials (adhesives).
In recent years, a decorative sheet covering material obtained by wrapping an adherend such as a medium fiberboard (MDF) with a decorative sheet such as a vinyl chloride film using this type of adhesive has been widely used. Such a decorative sheet coating material is used for furniture, building materials, and the like because it gives various patterns to the surface of an inexpensive core material, a highly durable core material, and the like, and gives added value such as a high-class feeling.

However, this type of polyurethane adhesive does not have sufficient initial adhesion. For example, when a decorative sheet coating material is produced by coating and adhering a decorative sheet to a core material having a curved surface or an uneven surface using this adhesive, the decorative sheet is immediately after bonding due to the repulsion of the decorative sheet. It is difficult to obtain a product with good quality due to floating between the curved surface of the core material and the uneven surface.
It is known to incorporate tackifiers to improve the initial adhesion of polyurethane adhesives. Examples of the tackifier include terpene resins, phenol resins, terpene phenol resins, rosin resins, and xylene resins (see, for example, Non-Patent Document 1).
However, even when a polyurethane adhesive blended with the above tackifier is used, when the decorative sheet is coated and adhered to a core material having a curved surface or an uneven surface, the decorative sheet and the core material are bonded immediately after bonding. The float still occurs between the curved surface or the uneven surface, and the initial adhesiveness is still insufficient. Moreover, when such a tackifier is mix | blended, there also exists a problem that the heat resistance of a polyurethane adhesive falls.

In order to solve the above problems, in Patent Document 1, a thermoplastic polyester urethane resin is blended with a phenol-modified xylene formaldehyde resin or / and a phenol-modified mesitylene formaldehyde resin as a tackifier and dissolved in a solvent; A polyurethane adhesive comprising an isocyanate curing agent is disclosed.
However, the two-component mixed solvent-based adhesive is suitable for bonding a vinyl chloride resin film. However, when this adhesive is used, for example, for bonding a polyolefin-based film, there is a problem in adhesive strength.

Patent Document 2 discloses a polyisocyanate having a hydroxyl group-containing thermoplastic polyester urethane resin, a main component containing a tackifier resin having an acid value of 10 mgKOH / g or less and a specific imidazole compound, and two or more active isocyanate groups. An adhesive composition comprising a curing agent containing a compound is disclosed. The adhesive composition described in Patent Document 2 has improved adhesion to a polyolefin-based film, but the initial adhesiveness is still insufficient, and suppresses floating immediately after the decorative sheet and the adherend are bonded together. There was a problem that I couldn't.
Japanese Unexamined Patent Publication No. 6-200229 JP 2000-53938 A September 25, 1987 Published by Nikkan Kogyo Shimbun, "Polyurethane Resin Handbook", pages 441-445

  An object of the present invention is to provide an adhesive composition that exhibits excellent initial adhesiveness, normal adhesive strength, and heat resistance with respect to a hardly adhesive polyolefin film.

  In order to solve the above problems, the adhesive composition of the present invention includes (A) a hydroxyl group-containing thermoplastic polyester urethane resin, (B) a solvent, (C) an amine-modified urethane resin, and (D) a polyisocyanate compound. It is characterized by that.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which exhibits the outstanding initial stage adhesiveness, normal-state adhesive strength, and heat resistance with respect to the poorly-adhesive polyolefin-type film can be provided.
The adhesive composition of the present invention can exhibit strong adhesive strength within several tens of seconds, is extremely excellent in initial adhesiveness, and is difficult to adhere to a decorative sheet such as a vinyl chloride film and a polyolefin film. It is possible to suppress the floating immediately after bonding the adherend and the adherend, and it is particularly suitably used for wrapping using a decorative sheet.

  Embodiments of the present invention will be described below, but these are exemplarily shown, and it goes without saying that various modifications are possible without departing from the technical idea of the present invention.

  The adhesive composition of the present invention comprises (A) a hydroxyl group-containing thermoplastic polyester urethane resin, (B) a solvent, (C) an amine-modified urethane resin, and (D) a polyisocyanate compound.

  The (A) hydroxyl group-containing thermoplastic polyester urethane resin (hereinafter also referred to as a polyester urethane resin (A)) is not particularly limited as long as it is a thermoplastic polyester urethane resin containing a hydroxyl group. A resin composed of a linear polymer obtained by addition polymerization reaction of at least one polyester resin and an active polyisocyanate compound is preferably used. The said polyester urethane resin (A) may be used independently and may be used together 2 or more types.

  A method for producing a polyester resin having two or more active hydroxyl groups is not particularly limited, and for example, a saturated polyester resin obtained by a condensation reaction of a polybasic acid and a dihydric alcohol is preferable. Examples of the polybasic acid include adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, and succinic acid. Examples of the dihydric alcohol include propylene glycol, ethylene glycol, tetramethylene glycol, butanediol, hexanediol, and neopentyl glycol.

  Examples of the active polyisocyanate compound include aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), and xylylene diisocyanate (XDI); hexamethylene diisocyanate (HDI), and lysine methyl. Aliphatic diisocyanates such as ester diisocyanate (LDI); alicyclic diisocyanates such as dicyclohexylmethane diisocyanate (HMDI) and isophorone diisocyanate (IPDI), and the like, and aliphatic diisocyanates are more preferred.

  The weight average molecular weight of the polyester urethane resin (A) is not particularly limited, but is preferably 100,000 to 400,000. By setting the weight average molecular weight of the polyester urethane resin (A) within the above range, the initial adhesiveness and normal adhesive strength of the adhesive composition of the present invention can be further improved.

The solvent (B) is preferably an organic solvent containing no active hydrogen, for example, hydrocarbons such as toluene, xylene, cyclohexane, etc .; halogenated hydrocarbons such as 1,1,1-trichloroethane, carbon tetrachloride; methyl ethyl ketone And ketones such as methylacetone; esters such as ethyl acetate and ethyl propionate.
These are used alone or in admixture of two or more, and contribute as a viscosity modifier.
Although there is no restriction | limiting in the mixture ratio of the said (B) solvent in the adhesive composition of this invention, 100-900 weight part is preferable with respect to 100 weight part of (A) polyester urethane resin.

The (C) amine-modified urethane resin is not particularly limited as long as it is a urethane resin modified with an amine. For example, a polyisocyanate compound and an active hydrogen-containing compound are reacted, and preferably an NCO / OH equivalent ratio of 1. After obtaining a urethane prepolymer of 10 to 10.00, more preferably 1.25 to 5.00, the urethane prepolymer and an amine compound can be obtained by reacting in the presence of a solvent, if necessary. it can. The NCO / active hydrogen equivalent ratio of the amine-modified urethane resin is preferably 1.00 to 2.00, and more preferably 1.00 to 1.20.
The amine-modified urethane resin used in the present invention is preferably dissolved in a solvent in order to prevent solidification. As the solvent for dissolving the amine-modified urethane resin, a solvent may be added after the production, or a solvent added during the production may be used as described above.

The active hydrogen-containing compound is not particularly limited as long as it is a compound containing an active hydrogen group, but monool or polyol is preferable, polyether polyol or polyester polyol is more preferable, and polyether polyol is more preferable. .
More specifically, for example, as the polyether polyol, one or two kinds of diols such as ethylene glycol, propylene glycol and butylene glycol, triols such as glycerin and trimethylolpropane, and amines such as ammonia and ethylenediamine are used. Examples include polyether polyols such as random or block copolymers obtained by ring-opening polymerization of propylene oxide and / or ethylene oxide in the presence of the above.
Examples of polyester polyols include polyester polyols such as copolymers obtained by polycondensation of adipic acid, sebacic acid, terephthalic acid, etc. in the presence of ethylene glycol, propylene glycol, 1,4 butanediol, neopentyl glycol, etc. In addition, low molecular active hydrogen compounds having two or more active hydrogen groups such as bisphenol A and ramester of castor oil can be mentioned.
As the active hydrogen-containing compound, those having a molecular weight of 100 to 20000 and 1 to 4 OH groups in one molecule can be preferably used.

  Examples of the polyisocyanate compound include aromatic polyisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI) and lysine methyl ester diisocyanate. Cycloaliphatic polyisocyanates such as isocyanates, hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, and hydrogenated tolylene diisocyanate can be mentioned. Among these, MDI is preferably used from the viewpoint of toxicity and price.

As the amine compound, primary and secondary amines can be used, and primary amines are preferred. Moreover, although both monoamine and polyamine can be used, polyamine is preferable and diamine is more preferable.
Examples of the polyamine include aliphatic diamines such as ethylenediamine, 1,3-diaminopropane, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, and neopentanediamine; 4,4′-diaminocyclohexylmethane, Cycloaliphatic diamines such as isophoronediamine, bisaminomethylcyclohexane, 2,5- or 2,6-diaminomethylbicyclo [2,2,1] heptane, diaminocyclohexane; diaminodiphenylmethane, diaminodiphenyl ether, xylylenediamine, phenylenediamine Aromatic diamines such as 3,5-diethyl-2,4- or 2,6-diaminotoluene; 1,3,5-tris (aminomethyl) benzene, 1,3,5-tris (aminomethyl) cyclohexane Aromatic or alicyclic triamines such as sun; obtained by converting the hydroxyl group of polyoxyalkylene glycols obtained by addition polymerization of propylene oxide and / or ethylene oxide to water, ethylene glycol, propylene glycol, etc. to amino groups Polyoxyalkylene diamines such as polyoxyalkylene triamines obtained by converting the hydroxyl groups of polyoxyalkylene triols obtained by addition polymerization of propylene oxide and / or ethylene oxide to glycerin, trimethylolpropane, etc. to amino groups, etc. Can be mentioned.
Examples of the monoamine include aliphatic primary amines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, amylamine, and hexylamine; aliphatics such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, and dibutylamine. Secondary amines; aliphatic unsaturated amines such as allylamine and diallylamine; cycloaliphatic amines such as cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine; aniline, diphenylamine, methylaniline, ethylaniline, toluidine, xylidine, benzylamine And aromatic amines such as naphthylamine.

  In the production of the amine-modified urethane resin, a low molecular compound having two or more active hydrogen groups in the molecule (for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, 1,6- Diols such as hexanediol and bisphenol A; polyhydric alcohols such as glycerin, trimethylolpropane, glucose, sorbitol, and shoelace; amines such as ethylenediamine and butylenediamine) may be used.

Although there is no restriction | limiting in the mixture ratio of the said (C) amine modified urethane resin in the adhesive composition of this invention, 20-600 weight part is preferable with respect to 100 weight part of (A) polyester urethane resin, 60-420 weight. Part is more preferred. By setting the blending amount of the (C) amine-modified urethane resin within the above range, the initial adhesiveness of the adhesive composition of the present invention can be further improved.
These (C) amine-modified urethane resins may be used alone or in combination of two or more.

The (D) polyisocyanate compound is not particularly limited as long as it has two or more isocyanate groups. For example, diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and dicyclohexylmethane diisocyanate. Dimers of these diisocyanates (carbodiimide-modified), trimers; triisocyanates such as triphenylmethane triisocyanate; crude MDI (also called polymeric MDI) which is a mixture of diphenylmethane diisocyanate, triphenylmethane triisocyanate, etc. (Polyisocyanate compounds that are liquid at room temperature, such as (methylene diisocyanate) The urethane prepolymer and the like having an active isocyanate group obtained by a reaction between Lumpur 2 or more. As the liquid polyisocyanate compound, crude MDI is more preferable from the viewpoint of viscosity and price. As the urethane prepolymer, the urethane prepolymer described in the description of the amine-modified urethane resin is preferably used.
These polyisocyanate compounds may be used alone or in combination of two or more, but it is preferable to use a liquid polyisocyanate compound and a urethane prepolymer in combination.

Although there is no restriction | limiting in the mixture ratio of the said (D) polyisocyanate compound in the adhesive composition of this invention, 10-700 weight part is preferable with respect to 100 weight part of (A) polyester urethane resin.
In particular, when the urethane prepolymer described above is used as the (D) polyisocyanate compound, 30 to 600 parts by weight is preferable and 60 to 420 parts by weight is more preferable with respect to 100 parts by weight of the (A) polyester urethane resin. By making the compounding quantity of the said urethane prepolymer into the said range, the normal-state adhesive strength of the adhesive composition of this invention, initial stage adhesiveness, and heat resistance can be improved more.
Moreover, when using the liquid isocyanate compound mentioned above as (D) polyisocyanate compound, 10-100 weight part is preferable with respect to 100 weight part of (A) polyester urethane resin, and 20-80 weight part is more preferable. By making the compounding quantity of the said liquid isocyanate compound into the said range, the heat resistance of the adhesive composition of this invention can be improved more.

  In addition to the components described above, the adhesive composition of the present invention includes a curing catalyst, an adhesion-imparting agent, a physical property modifier, a filler, a plasticizer, a thixotropic agent, a dehydrating agent (improving storage stability). Agents), tackifiers, sagging inhibitors, ultraviolet absorbers, antioxidants, flame retardants, colorants, radical polymerization initiators and the like.

The adhesive composition of the present invention can be a one-component type or a two-component type as required, but is preferably used as a two-component type.
When the adhesive composition of the present invention is used as a two-pack type, the polyester urethane resin (A) and, if necessary, the (B) solvent may be blended with the main agent, and the (D) polyisocyanate compound may be blended with the curing agent. preferable. (C) The amine-modified urethane resin may be blended in either the main agent or the curing agent when it does not contain an NCO group, but is preferably blended in the curing agent when it contains an NCO group.

  The present invention will be described more specifically with reference to the following examples. However, it is needless to say that these examples are shown by way of illustration and should not be construed in a limited manner.

(Synthesis Example 1)
In a stirrer equipped with a thermometer, 605.3 parts by weight of polypropylene glycol having a molecular weight of 2000 (trade name: Diol-2000, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) was dehydrated, and then 4,4-diphenylmethane diisocyanate (MDI). 94.7 parts by weight were added and reacted at 70 to 90 ° C. for 3 hours under a nitrogen stream to obtain urethane prepolymer X having an NCO / OH equivalent ratio of 1.25.

  In a stirrer equipped with a thermometer, 494.5 parts by weight of the obtained urethane prepolymer X and 500 parts by weight of ethyl acetate were added and uniformly dispersed, and ethylene oxide diamine having a molecular weight of 148 (manufactured by Huntsman, USA) Name: Jeffamine EDR-148) 5.5 parts by weight was added dropwise to obtain an amine-modified urethane resin C1 having a solid content of 50% and an NCO / active hydrogen equivalent ratio of 1.00.

(Synthesis Example 2)
After synthesizing urethane prepolymer X as in Synthesis Example 1, in a stirrer equipped with a thermometer, 492.2 parts by weight of urethane prepolymer X and 500 parts by weight of ethyl acetate were added and dispersed uniformly. 7.8 parts by weight of butylamine having a molecular weight of 73 was dropped to obtain an amine-modified urethane resin C2 having a solid content of 50% and an NCO / active hydrogen equivalent ratio of 1.00.

(Synthesis Example 3)
In a stirrer equipped with a thermometer, 589.3 parts by weight of polypropylene glycol having a molecular weight of 2000 (trade name: Diol-2000, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) was dehydrated, and then 4,4-diphenylmethane diisocyanate (MDI). 110.7 parts by weight were added and reacted at 70 to 90 ° C. for 3 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO / OH equivalent ratio of 1.50 (hereinafter referred to as polyisocyanate compound D1).

Example 1
100 parts by weight of Pandex T-5202 (manufactured by Dainippon Ink & Chemicals, Inc.) as a hydroxyl group-containing thermoplastic polyester urethane resin was uniformly dissolved in 400 parts by weight of ethyl acetate to prepare a main component of the adhesive composition. .
Further, the amine-modified urethane resin C1 obtained in Synthesis Example 1, the polyisocyanate compound D1 obtained in Synthesis Example 3, and Cosmonate M-300 (Mitsui Chemical Polyurethane Co., Ltd., special polymeric MDI that is liquid at room temperature, the following The polyisocyanate compound D2) was stirred and mixed at a blending ratio shown in Table 1 under a nitrogen stream to prepare a curing agent for the adhesive composition.
The obtained main agent and curing agent were uniformly stirred and mixed at a blending ratio shown in Table 1 to prepare an adhesive composition of the present invention.

  In Table 1, the blending amount of each material is parts by weight, polyester urethane resin A1 is a product name “Pandex T-5202” manufactured by Dainippon Ink and Chemicals, and amine-modified urethane resin C1 is a synthesis example. The amine-modified urethane resin C1 and the polyisocyanate compound D1 obtained in 1 are the polyisocyanate compound D1 and the polyisocyanate compound D2 obtained in Synthesis Example 3, respectively, and trade name “Cosmonate M-300” manufactured by Mitsui Chemicals Polyurethanes. .

While applying the adhesive composition obtained above to a polyolefin film with an applicator in a thickness of 100 μm, passing it through a hot air drying oven at 40 ° C., and covering the adherend made of electrodeposited aluminum, A polyolefin film coating material was produced by pressure bonding with a pressure roller.
The following tests were performed on the obtained polyolefin film coating material. The results are shown in Table 2.

(1) Initial adhesion The plane part of the polyolefin film coating material immediately after production was cut into dimensions of 100 mm in length and 25 mm in width, and one end part of the polyolefin film was peeled in advance, and this was held at 23 ° C. for 1 minute. Thereafter, the upper end of the adherend was fixed while holding it vertically, and a weight of 250 g was attached to one end of the polyolefin film, and the 180-degree peel length after 1 minute was measured in an atmosphere at 23 ° C. The evaluation criteria are as follows.
A: Less than 11 mm, O: 11 mm or more and less than 16 mm, Δ: 16 mm or more and less than 26 mm, X: 26 mm or more.
In the present invention, the initial adhesiveness refers to the adhesiveness within 2 minutes from immediately after pressure-bonding with a pressure roller while applying an adhesive composition to a polyolefin film and covering an adherend made of electrodeposited aluminum. Means.

(2) Normal adhesion strength A plane part of a polyolefin film coating material immediately after production was cut into dimensions of 100 mm in length and 25 mm in width, and one end of the polyolefin film was peeled in advance to prepare a test piece. The test piece immediately after the production was cured at 23 ° C. for 24 hours, and then the adherend and one end of the polyolefin film were fixed to the chuck, and using an autograph in an atmosphere of 23 ° C.-50% RH, a tensile rate of 200 mm / A 180 ° peel test was performed in minutes to determine the normal bond strength (N / 25 mm). The evaluation criteria are as follows.
A: 50 N / 25 mm or more, B: 40 N / 25 mm or more and less than 50 N / 25 mm, Δ: 30 N / 25 mm or more and less than 40 N / 25 mm, X: less than 30 N / 25 mm.

(3) Heat resistance creep property The plane part of the polyolefin film coating material immediately after production was cut into dimensions of 100 mm in length and 25 mm in width, and one end part of the polyolefin film was peeled in advance, and this was held at 23 ° C. for 24 hours. Thereafter, the upper end of the adherend was held vertically and a 500 g weight was attached to one end of the polyolefin film, and the 180-degree peel length after 24 hours was measured in an atmosphere at 60 ° C. The evaluation criteria are as follows.
A: Less than 6 mm, B: 6 mm or more and less than 11 mm, Δ: 11 mm or more and less than 21 mm, X: 21 mm or more.

(Examples 2 to 11)
As shown in Table 1, an adhesive composition and a polyolefin film coating material were prepared and tested in the same manner as in Example 1 except that the composition was changed. The results are shown in Table 2.

(Examples 12 to 20)
As shown in Table 3, an adhesive composition and a polyolefin film coating material were prepared and tested in the same manner as in Example 1 except that the composition was changed. The results are shown in Table 4.

  In Table 3, the compounding quantity of each material is a weight part, Polyester urethane resin A1 is Dainippon Ink and Chemicals Co., Ltd. product name "Pandex T-5202", Amine modified urethane resin C1 is a synthesis example. The amine-modified urethane resin C1 and the polyisocyanate compound D1 obtained in 1 are the polyisocyanate compound D1 and the polyisocyanate compound D2 obtained in Synthesis Example 3, respectively, and trade name “Cosmonate M-300” manufactured by Mitsui Chemicals Polyurethanes. .

(Examples 21 to 25)
As shown in Table 5, an adhesive composition and a polyolefin film coating material were prepared and tested in the same manner as in Example 1 except that the composition was changed. The results are shown in Table 6.

  In Table 5, the blending amount of each material is parts by weight, polyester urethane resin A1 is a product name “Pandex T-5202” manufactured by Dainippon Ink and Chemicals, and amine-modified urethane resin C2 is a synthesis example. The amine-modified urethane resin C2 and the polyisocyanate compound D1 obtained in 2 are the polyisocyanate compound D1 and the polyisocyanate compound D2 obtained in Synthesis Example 3, and are trade names “Cosmonate M-300” manufactured by Mitsui Chemicals Polyurethanes, Inc. .

(Comparative Examples 1-7)
As shown in Table 7, an adhesive composition and a polyolefin film coating material were prepared and tested in the same manner as in Example 1 except that the composition was changed. The results are shown in Table 8.

  In Table 7, the compounding quantity of each material is a weight part, The polyester urethane resin A1 is Dainippon Ink and Chemicals Co., Ltd. make, brand name "Pandex T-5202", Amine modified urethane resin C1 is the synthesis example 1. The obtained amine-modified urethane resin C1 and polyisocyanate compound D1 are the polyisocyanate compound D1 and polyisocyanate compound D2 obtained in Synthesis Example 3, and are trade names “Cosmonate M-300” and t-butylphenol manufactured by Mitsui Chemicals Polyurethanes, Inc. The modified xylene formaldehyde resin is a product name “Nikanol HP100” manufactured by Mitsubishi Gas Chemical Co., Ltd., the terpene phenol resin is a product name “Tamanol 803” manufactured by Arakawa Chemical Industries, Ltd., and the rosin ester resin is manufactured by Arakawa Chemical Industry Co., Ltd. "Ester gum H", ketone resin is a product manufactured by Honshu Chemical Industry Co., Ltd. It is the "Ha Long 80".

Claims (1)

(A) a hydroxyl group-containing thermoplastic polyester urethane resin,
(B) solvent,
An adhesive composition comprising: (C) an amine-modified urethane resin; and (D) a polyisocyanate compound.