JP3426621B2 - Adhesive composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive. More specifically, the present invention relates to an adhesive composition comprising a polyurethane having a specific structure, a polyisocyanate having a specific structure, an organotin compound, and acetylacetone. [0002] The adhesive composition of the present invention has a long pot life,
Since the obtained adhesive has excellent durability and adhesive strength, it can be suitably used for industrial laminates such as cloths and laminates such as synthetic leathers. [0003] Conventionally, polyurethane adhesives have been used in the field of industrial lamination of fabrics and the like, and in the field of lamination of synthetic leather and the like. When excellent durability is required, polylactone, polycarbonate, polyether and the like are used as the polymer polyol which is a raw material of polyurethane. Further, as disclosed in JP-A-62-181376, JP-A-63-182587, and JP-A-62-64880, a polyurethane-based adhesive using a polyester polyol having a specific structure is disclosed. It is known to have excellent durability. It is well known that when yellowing or the like is a problem, a compound using an aliphatic polyisocyanate as a crosslinking agent is used. [0005] Japanese Patent Application Laid-Open No. 24395/1992 discloses a coating composition having a long pot life. However, the composition described in this publication relates to a paint, and no resin is selected as an adhesive. In addition, since the polyisocyanate used as a cross-linking agent is a polyisocyanate using isophorone diisocyanate as a raw material, when used for an adhesive, there is a problem that the amount of coating is large or the aging temperature is low, so that curing is slow. [0006] In recent years, there has been a remarkable trend in the trend toward higher-grade consumerism and the emphasis on sensitivity and fashion. For example, a laminate of a fabric and a polyester film, such as a surf sale, requires a strong adhesive force and hydrolysis resistance for the adhesive layer, and furthermore, the adhesive layer does not turn yellow in order to maintain its beauty and fashionability. Is required. In the fields of synthetic leather, artificial leather, etc., excellent durability is required in combination with strong adhesive strength. In addition, in the case of light-colored products, yellowing of the adhesive layer causes a change in appearance. It is also required that the adhesive layer does not yellow. For the above purposes and applications, a non-yellowing polyisocyanate compound is used as a crosslinking agent for the polyurethane adhesive. However, the non-yellowing polyisocyanate compound is an aliphatic or alicyclic polyisocyanate compound, and therefore has poor reactivity. Therefore, organometallic catalysts such as organotin compounds and organoiron compounds are used for the purpose of accelerating the crosslinking reaction. However, since these metal-based catalysts have high temperature sensitivity, there has been a problem that the viscosity of the adhesive composition increases sharply in summer and the pot life becomes extremely short. On the other hand, in winter, there is a problem that curing is slow and long-term curing is required. [0007] An object of the present invention is to provide excellent adhesive strength and durability.
An object of the present invention is to provide an adhesive composition which has little yellowing and has a long pot life. [0008] According to the present invention, the above objects are provided by A.I. Polylactone, polycarbonate, polye
And carbon atoms of 6 or more and 10 or less shown in the following chemical formula 2.
The following alkanediol and dicarboxylic acid or its ester
Reaction of at least one polymer polyol selected from the group consisting of polyesters obtained by reacting with a polyester-forming derivative and having two or more primary hydroxyl groups in one molecule with diisocyanate. A polyurethane polyol obtained at a minimum: (In the formula, m and n represent an integer of 1 to 6, and R represents a hydrogen atom or a methyl group.) An organic solvent having no activated hydrogen, C.I. Adduct of hexamethylene diisocyanate with polyol having 3 or more hydroxyl groups in one molecule
Parts by weight (based on 100 parts by weight of A) 0.005 to 0.40 parts by weight of the organotin compound (based on A
100 parts by weight). This is achieved by using an adhesive composition comprising acetylacetone in an amount of 10 to 100 times the weight of the above-mentioned organotin compound. First, the polymer polyol which is a raw material of the polyurethane polyol of the component A used in the present invention will be described. The polyester used in the present invention can be obtained by reacting a specific alkanediol represented by the above formula (2) with a dicarboxylic acid or an ester-forming derivative thereof under the conditions employed in a usual polyester formation reaction. . Examples of the specific alkanediol include 3-methyl-1,5-pentanediol, 1,6-
Examples include hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. If the specific alkanediol has less than 6 carbon atoms, the durability, especially the wet heat resistance, of the polyurethane polyol may be deteriorated. On the other hand, if the number of carbon atoms is larger than 10, when the polyurethane polyol is used, the obtained adhesive becomes hard, and the feeling of the obtained adhesive may deteriorate, or the cold resistance may deteriorate. Representative examples of dicarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, and sebacic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid. These dicarboxylic acids are used alone or in a mixture of two or more. Of these, aliphatic dicarboxylic acids, especially adipic acid and sebacic acid, are preferably used. These dicarboxylic acids may be used in the form of an ester-forming derivative. Representative examples of such a case include lower alkyl esters such as methyl and ethyl esters of the above-described dicarboxylic acids. The above dicarboxylic acids or ester-forming derivatives thereof are used alone or in a mixture of two or more. Examples of polylactone include poly-ε-caprolactone, poly-β-methyl-δ-valerolactone and the like. These polylactones are produced by subjecting lactones to ring-opening polymerization using an alkylene glycol or the like as an initiator. Polycarbonate is produced by a transesterification reaction between an alkylene glycol and a carbonate or a reaction between phosgene or chloroformate and an alkylene glycol. As the alkylene glycol, for example, an oxygen atom is interposed in an alkylene portion such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and diethylene glycol. Linear alkylene glycol having 2 to 10 carbon atoms, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol 4 to 10 carbon atoms such as
Are used alone or in a mixture of two or more. Representative examples of the carbonate include diphenyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate and the like. Examples of the polyether include polyethylene glycol and polytetramethylene glycol. Among them, polytetramethylene glycol is preferably used from the viewpoint of wet heat resistance. The polymer polyol preferably has a number average molecular weight in the range of 700 to 10,000, more preferably 1000 to 3000, based on the hydroxyl value. Adhesives produced using a polymer polyol having a number average molecular weight of less than 700 may lose flexibility. The number average molecular weight is 1000
Adhesives composed of polyurethanes produced using more than zero polymer polyols may have poor adhesion. Examples of the diisocyanate which is one of the raw materials for producing the polyurethane polyol used in the present invention include known aliphatic, alicyclic or aromatic diisocyanates. Preferred examples include tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and the like. When particularly excellent yellowing resistance is required, it is preferable to use an aliphatic or alicyclic diisocyanate. However, in a normal use, unlike the case of the diisocyanate of the component C described later, an aromatic diisocyanate is used. Even with certain diphenylmethane diisocyanate, yellowing resistance hardly causes a problem, and it is preferably used for economic reasons. The polyurethane polyol used in the present invention has a weight-average molecular weight in terms of polystyrene, determined by gel permeation chromatography, of 300.
It is preferably in the range of 00 to 300,000. In the case of an adhesive composition comprising a polyurethane polyol having a weight average molecular weight of less than 30,000, sufficient adhesive performance may not be exhibited, and in an adhesive composition comprising a polyurethane polyol having a weight average molecular weight exceeding 300,000, a May increase the viscosity, which may hinder use. Examples of the organic solvent having no activated hydrogen used as the component B of the present invention include methyl ethyl ketone,
Examples include methyl isobutyl ketone, toluene, ethyl acetate, dimethylformamide, dioxane, tetrahydrofuran and the like. The adduct of hexamethylene diisocyanate used as the component C of the present invention with a compound having three or more hydroxyl groups in one molecule functions as a crosslinking agent in the adhesive composition of the present invention. When the cross-linking agent uses an aromatic isocyanate, it has a problem of yellowing, and cannot be used in the present invention. In addition, diisocyanates having an isocyanate group bonded to a non-primary carbon such as isophorone diisocyanate or dicyclohexylmethane diisocyanate cannot be used in the present invention because curing is slow.
Examples of the adduct include an adduct of a tri- or tetravalent alcohol such as trimethylolpropane, glycerin or pentaerythritol with hexamethylene diisocyanate. The adduct is preferably used by adding 5 to 30 parts by weight to 100 parts by weight of the polyurethane polyol of the component A. More preferably, the amount is in the range of 8 to 25 parts by weight. If the amount of the adduct is less than 5 parts by weight, the adhesive strength may be insufficient. The adduct is 3
If the amount is more than 0 parts by weight, there may be a problem that the adhesive becomes hard and the feeling becomes poor. The organotin compound used as the component D in the present invention functions as an accelerator in curing the adhesive composition of the present invention, and is essential. As such an accelerator, an organic iron compound may be used to cure the adduct of the component C of the present invention in a practical time. However, since the compound is colored, it is preferably used when yellowing or concealing property is considered. Absent. Examples of the organotin compound include di-n-butyltin dilaurate, di-n-butyltin dioctoate, di-n-butyltin diacetate, and stannasoctoate. Among them, di-n-butyltin dilaurate and di-n-butyltin dioctoate are preferably used from the viewpoint of curing reaction acceleration and solvent solubility. The organotin compound is 0.005 to 100 parts by weight of the polyurethane polyol of the component A.
It is preferable to use it in addition to 0.30 parts by weight. More preferably, the amount is in the range of 0.01 to 0.20 parts by weight. If the amount of the organotin compound is less than 0.005 parts by weight (based on 100 parts by weight of A), poor curing may occur in winter. On the other hand, if the amount of the organotin compound is more than 0.40 part by weight (based on 100 parts by weight of A), there may be a problem that the deterioration of the polyurethane polyol of the component A is promoted. Acetylacetone used as the E component of the present invention is indispensable for making the pot life of the adhesive composition of the present invention practical. The amount of acetylacetone added is one of the organotin compounds used as the D component.
It is preferable that the amount is 0 to 100 times by weight. If the amount added is less than 10 times by weight, the pot life of the adhesive composition may be shortened. If the amount added is more than 100 times by weight, poor curing or coloring may occur. The method of processing the adhesive composition of the present invention is a method of applying an adhesive to a substrate, removing a solvent or the like with a drier, and then bonding the substrate to another substrate. As a suitable processing method, a method or a wet lamination method in which an adhesive is applied to a base material, and the base material is bonded to another base material in a wet state, and then a solvent or the like is dried and removed with a drier. The adherend obtained by processing the adhesive composition of the present invention by, for example, the above-mentioned lamination method is cured in an atmosphere of about 20 ° C. to 60 ° C. so that practical adhesive strength can be obtained in a practical required number of days. It is possible to express. The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, parts and% relate to weight unless otherwise specified. Further, the compounds may be indicated by the following abbreviations. HDI: hexamethylene diisocyanate TDI: tolylene diisocyanate IPDI: isophorone diisocyanate MPD: 3-methyl-1,5-pentanediol ND: 1,9-nonanediol MOD: 2-methyl-1,8-octanediol PMPA _1000: MPD and polyester diols PNOA having a number average molecular weight of 1000 obtained by condensation polymerization of adipic acid _1000: the number-average molecular weight of the equimolar mixture of adipic acid obtained by condensation polymerization of ND and MOD 1000 polyester diol PCL _1000: number-average molecular weight of 1000 obtained by ring-opening polymerization of ε- caprolactone polycaprolactone diol PHC _1000: the number of average molecular weight 1000 polyhexylene carbonate diol TG _1000: The number-average molecular weight of 1000 polytetramethylene glycol PEA _1000: The number-average molecular weight 1000 polyethylene adipate diol PBA _1000: The number of average molecular weight 1000 polybutylene adipate Tojioru [0027] Polymer Preparation Example number average molecular weight of 1,000 of the polyurethane polyol Polyol PMPA
_{1000 1000} g and N, N-dimethylformamide (DM
F) 174 g and 322 g of toluene were charged into a three-necked flask equipped with a Dimroth condenser and heated to obtain a homogeneous solution. Thereafter, 157 g of TDI was charged as a diisocyanate, and reacted at 85 ° C. for about 8 hours in a nitrogen atmosphere to give a concentration of 7.
A 0% by weight polyurethane solution A was obtained. The resulting polyurethane solution was diluted with dimethylformamide to give 0.5%.
% By weight, and gel permeation chromatography (developing solvent: dimethylformamide; flow rate: 1.
0 ml / min), and the weight average molecular weight (in terms of polystyrene) of the polyurethane was measured. As a result, the weight average molecular weight was 87,600. As a measuring device in gel permeation chromatography,
Yanagimoto pump L-4000W, Showa Denko column showdex KF805 and KF803 (consolidated), and Showa Denko RI detector SE51 were used. Hereinafter, polyurethane solutions used as Examples and Comparative Examples were obtained in the same manner. However, when IPDI was used as the diisocyanate, the reactivity was poor. Therefore, 10 ppm of dibutyltin dilaurate was added as a catalyst with respect to the total amount of solids, and polymerization was carried out. Table 1 shows the obtained polyurethane solutions. [Table 1] Examples 1 to 3 and Comparative Examples 1 to 4 The resulting polyurethane solutions A, B, C, F and G were further blended with the compositions shown in Table 2 to obtain adhesive compositions. The adhesive composition was applied to various tests described below. Table 2 shows the results. Pot Life The viscosity of the adhesive composition was measured using a B-type viscometer immediately after preparation and after standing at 40 ° C. for 6 hours [ps]. Adhesive strength A polyethylene terephthalate film (Lumirror manufactured by Toray, thickness 65 μm) was subjected to the pot life test described above, and the adhesive composition passed for 6 hours.
/ M ² , dried at 70 ° C. for 1 minute, and bonded to polyester taffeta to obtain an adhesive sample. After the obtained adhesive sample was cured at 20 ° C. for one day, it was peeled at 180 ° at a pulling speed of 50 mm / min, and the adhesive strength [kg / 2.5 cm] was observed. Wet heat test After the obtained adhesive sample was exposed to an atmosphere of 70 ° C. and 95% RH for 2 weeks, a 180 ° peel strength [kg / 2.5
cm]. Light fastness test According to JIS L-0842, a light fastness test was performed at 63 ° C. by irradiating with a carbon arc lamp, and a class was determined. In addition,
For the test, Suga Test Machine Co., Ltd.'s light fastness tester F-AL-5
Type H was used. [Table 2] In the tables, all compositions are by weight. The HDI adduct is a reaction product of HDI and trimethylolpropane. As shown in the data of Examples 1 to 3 and Comparative Examples 1 and 2, the polyurethane adhesive composition of the present invention using a diol having a specific structure having 6 to 10 carbon atoms has excellent durability. It can be seen that it has. Further, without acetylacetone, which is indispensable for extending the pot life of the adhesive composition of the present invention, the pot life becomes extremely short as seen in Comparative Example 3.
On the other hand, if the amount of acetylacetone is too large, the development of the adhesive strength may be delayed as seen in Comparative Example 4. Examples 4 to 5 and Comparative Examples 5 to 8 The obtained polyurethane solutions D and E were blended according to the composition shown in Table 3 to obtain an adhesive composition. Table 3 shows the evaluation results of the adhesive composition. [Table 3] The HDI adduct is a 1: 3 adduct of HDI and trimethylolpropane. The IPDI adduct is a 1: 3 adduct of IPDI and trimethylolpropane. The TDI adduct is a 1: 3 adduct of TDI and trimethylolpropane. As can be seen from the data of Example 4 and Comparative Examples 5 and 6, the polyisocyanate used as a crosslinking agent in the adhesive composition of the present invention is disadvantageous unless it is a polyisocyanate composed of hexamethylene diisocyanate. Further, from the data of Example 5 and Comparative Examples 7 and 8, it can be seen that if there is no tin compound used as an accelerator, curing will be poor, and if too much, the durability of the adhesive will be poor. Since the adhesive composition of the present invention has a long pot life and is excellent in adhesive strength, durability, light resistance and the like, it can be used for laminating a transparent or light-colored film with a fabric or for synthesizing. It can be particularly suitably used for laminating a light-colored film such as leather and a nonwoven fabric.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-182237 (JP, A) JP-A-62-181376 (JP, A) JP-A-59-27967 (JP, A) JP-A-49-1979 339 (JP, A) JP-A-55-58278 (JP, A) JP-A-62-64880 (JP, A) JP-A-3-281589 (JP, A) JP-A-63-182387 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) C09J 175/00-201/10 C08G 18/00-18/87

Claims (1)

(57) [Claims] [Claim 1] A. Polylactone, polycarbonate,
Polyether, and C6 or less represented by the following chemical formula 1
No more than 10 alkanediols and dicarboxylic acids or
Polyester obtained by reacting with an ester-forming derivative of
A polyurethane polyol selected from the group consisting of stells and having at least one polymer polyol having two or more primary hydroxyl groups in one molecule and obtained by reacting a diisocyanate with: (In the formula, m and n represent an integer of 1 to 6, and R represents a hydrogen atom or a methyl group.) An organic solvent having no activated hydrogen, C.I. Adduct of hexamethylene diisocyanate with polyol having 3 or more hydroxyl groups in one molecule
Parts by weight (based on 100 parts by weight of A) 0.005 to 0.40 parts by weight of the organotin compound (based on A
100 parts by weight). An adhesive composition comprising acetylacetone in an amount of from 10 to 100 times the weight of the organotin compound.