JPH08302183A - Curable urethane resin composition, and adhesive - Google Patents

Abstract

PURPOSE: To obtain a curable urethane resin composition which, when used as an adhesive, gives such tack characteristics and final adhesion that the tackiness can be developed more quickly under low temperature and low humidity conditions and the bonding range can be lengthened under high temperature and high humidity conditions while maintaining the final bonding strength of the adhesive. CONSTITUTION: This composition contains an aromatic hydrocarbon compound having a difference of at most 15 deg.C between the melting initiation temperature and the melting point on the chart determined by a differential scanning calorimeter, with a melting initiation point of 30-150 deg.C and a melting point of 35-165 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable urethane resin composition and an adhesive having excellent adhesive property and final adhesive property by containing a compound having a specific melting point and a melting start point in DSC. .

[0002]

Urethane resins are widely used in various industrial fields including automobiles, civil engineering, and construction. There are various uses such as sealants in the waterproofing field of buildings, but for example, adhesives for on-site construction of waterproof cushion sheets as described in "Construction Standard Specifications / Commentary JASS 8 Waterproofing (1993)". Is also used as

The waterproof cushioning sheet is generally made of synthetic rubber such as ethylene propylene rubber, chlorosulfonated polyethylene, vinyl chloride resin, chlorinated polyethylene, and butyl rubber, and these wound sheets are adhered to a base material such as a concrete base. In addition, a strong initial adhesive strength of the adhesive is required for adhesion.

Conventionally, as the adhesive for the waterproof cushioning sheet, a so-called rubber glue type in which a synthetic rubber such as polyisobutylene rubber, chloroprene rubber or isoprene rubber is diluted with an organic solvent has been used. These adhesives have sufficient tackiness to bring the above-mentioned waterproof cushioning sheet into close contact, but since the formed adhesive layer does not have a cross-linking structure, it is thermoplastic and has a low softening point. The strength is significantly reduced. That is, it has a defect of poor heat resistance.

To solve this problem, curable urethane adhesives which form a crosslinked structure under room temperature conditions have been used in recent years. There are two types of adhesives, two-component curable and one-component curable. The former cures by the reaction of isocyanate with active hydrogen, and the latter cures isocyanate with moisture in the base material and moisture in the atmosphere. The reaction cures. Since both are so-called thermosetting resins, they have excellent heat resistance and durability.

One of the remaining problems of these adhesives is that they require skill in construction. Especially in one-part moisture curing, the curing reaction is a reaction with moisture, so the adhesiveness is different between the low temperature and low humidity conditions in winter and the high temperature and high humidity conditions in summer, and the adhesiveness is easily influenced by the external environment. , It is necessary to carefully control the open time between applying the adhesive and pasting the sheet. For example, in the winter, the reaction is slow and the initial adhesive strength is poorly expressed, so the sheet cannot be fixed to the ground unless the open time is considerably long. However, there is a problem that the adhesion between the sheet and the base deteriorates after a longer time. Although the open time is set in consideration of work efficiency, it takes about 30 minutes or more to develop tackiness in the winter with a one-part moisture-curable adhesive, and within 60 minutes to maintain adhesion in the summer. I had to say. There is a similar tendency in the two-part curability, regardless of the time difference.

In order to solve these problems, the use of various tackifying resins has been proposed. Examples of the tackifying resin include alkylphenol resin, terpene resin, terpene phenol resin, xylene formald resin, rosin, rosin ester, hydrogenated rosin and coumarone resin. However, it is known that these tackifying resins lower the final adhesive strength when the addition amount increases, and a resin that solves all the above problems has not yet been developed.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to maintain the final adhesive strength and to develop the tackiness development time at low temperature and low humidity. Fast, long bonding time under high temperature and high humidity,
That is, it is to provide a curable urethane resin composition and an adhesive having excellent final adhesiveness and adhesive properties.

[0009]

The present inventors have completed the present invention as a result of earnest research for solving the above-mentioned problems.

That is, the present invention is a curable urethane resin composition characterized by containing a compound having a temperature difference between a melting start point and a melting point within 15 ° C. by a differential scanning calorimeter, preferably a softening of the compound. The melting point in DSC is 30 to 150 ° C and the melting point is 35 to 165 ° C, preferably the compound is an aromatic hydrocarbon compound. More preferably, it is a polymer of a C _{8 to} C ₁₀ aromatic hydrocarbon fraction, preferably the aromatic hydrocarbon compound is one having a polymer shown in Chemical formula 2 as a main component, and preferably The present invention provides a curable urethane resin composition of a one-pack moisture-curable type and an adhesive agent using the same.

[0011]

Embedded image (N = integer of 2 to 4)

(Structure) The curable urethane resin composition used in the present invention is roughly classified into a one-component moisture-curable type and a two-component curable type. Considering the coating workability when used as an adhesive outdoors, the one-component moisture-curable type is preferable.

The one-pack moisture-curable type is a urethane compound having two or more free isocyanate groups, which is a urethane prepolymer prepared by a conventional method with an organic polyisocyanate and an organic polyhydroxyl compound in excess of isocyanate. is there.

Examples of the organic polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, partially carbodiimidated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, tolidine diisocyanate and naphthalene. Aromatic diisocyanate such as diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, aliphatic diisocyanate, alicyclic diisocyanate one or more kinds A mixture may be mentioned. Among them, diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate are preferable from the viewpoints of adhesive strength, economical efficiency and safety to human body.

The organic polyhydroxyl compound used in the present invention is a hydroxyl group-containing liquid diene polymer, hydrogenated products thereof, polyether polyols, polyester polyols, other polyols and mixed polyols thereof. For example, a polyol produced by using a complex metal cyanide compound complex as a catalyst is also included.

The hydroxyl group-containing liquid diene polymer means a diene polymer having 4 to 12 carbon atoms, a diene copolymer, and these diene monomer and an α-olefin addition polymerizable monomer having 2 to 22 carbon atoms. There are copolymers and the like. Specific examples include butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhexyl acrylate copolymer, butadiene-n-octadecyl acrylate copolymer, and the like. it can.

As the polyether polyol, one or more polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, glucose, sorbitol and sucrose are added to propylene oxide and ethylene. Examples thereof include polyols and polyoxytetramethylene polyols obtained by adding one kind or two or more kinds of oxides, butylene oxides, styrene oxides and the like.

As the polyester polyol, for example, one or two of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, trimethylolpropane or other low molecular weight polyols is used.
And one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, hydrogenated dimer acid or other low molecular weight dicarboxylic acid or oligomer acid. Examples thereof include condensation polymers and ring-opening polymers such as propiolactone, caprolactone and valerolactone.

Examples of other polyols include polycarbonate polyol and acrylic polyol. Also, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Low molecular weight polyols such as butanediol, pentanediol, hexanediol, cyclohexanedimethanolglycerin, trimethylolpropane, glucose, sorbitol and sucrose are also included.

Among these polyols, a hydroxyl group-containing liquid diene polymer having durability such as water resistance and tackiness, or a hydrogenated product thereof is preferable.

Next, the two-component curable urethane resin composition means a main agent composed of urethane prepolymer and the like and short chain glycols such as ethylene glycol and propylene glycol, or long chain polyols and polyamines having a molecular weight of 200 to 10,000. A curing agent containing a compound having active hydrogen such as those of the above-mentioned compounds has a free NCO / H ⁺ equivalent ratio of 0.5 to
It is cured at a ratio of 1.5.

The compounds of the present invention preferably have a softening point of 2.
0 ° C. or higher, more preferably 30 to 150 ° C., preferably the starting point of melting endothermic peak in the chart of a differential scanning calorimeter (hereinafter abbreviated as DSC), so-called melting starting point is 30 to 150 ° C. It is an apex having a melting point of 35 to 165 ° C. As the differential scanning calorimeter (DSC), DSC-8230B manufactured by Rigaku Denki Co., Ltd. was used. The measurement conditions are a temperature rising rate of 10 ° C./min, and the compound of the present invention has a difference between the melting start temperature and the melting point of the measured chart within 15 ° C., more preferably within 10 ° C. When the melting point of the compound is lower than 35 ° C. and the melting start point is lower than 30 ° C., the tackiness of the urethane resin is deteriorated. On the contrary, when the melting start point is higher than 150 ° C., the handling itself is deteriorated. .

Examples of such compounds include aromatic hydrocarbon compounds, thermoplastic urethane resins, ester compounds of monohydric alcohols and polybasic acids, and the like, but aromatic hydrocarbon compounds are preferred.

The aromatic hydrocarbon compound used in the present invention is preferably a polymer represented by a C _{8 to} C ₁₀ aromatic hydrocarbon fraction.

The C ₈ -C ₁₀ aromatic hydrocarbon fraction is, for example, ethylbenzene, o, m, p-xylene, isopropylbenzene, n-propylbenzene, 1-methyl-3-ethylbenzene, 1-methyl-4-. Ethylbenzene, 1,3,5-trimethylbenzene, 1-methyl-2-ethylbenzene, tert-butylbenzene, 1,2,4-trimethylbenzene, 1,2,3-trimethylbenzene, 1-methyl-3-propylbenzene , 1-methyl-2-propylbenzene, 1,4-dimethyl-2-ethylbenzene, 1,
2,4,5-tetramethylbenzene, 1,2,3,4-tetramethylbenzene, indene, o-, m-, p-vinyltoluene, α-, β-
Examples include methylstyrene, styrene, methylstyrene, methylindene, dicyclopentadiene and the like.

A polymer having an aromatic hydrocarbon fraction of C ₁₁ or more has a softening point of much higher than 150 ° C. and is difficult to handle, so that a C ₁₀ or less is preferable, and particularly C ₈
Is desirable. For the same reason, among the polymers of Chemical formula 3, a 4-ring aromatic hydrocarbon having a softening point of n = 2 around 40 ° C. is most preferable. When n = 1, the softening point is around 5 ° C., so that it becomes liquid at room temperature, and when it is added to the adhesive, the initial adhesive strength under low temperature and low humidity becomes weak.

The polymer of the C ₈ -C ₁₀ aromatic hydrocarbon fraction preferably contains the compound represented by Chemical formula 3 as the main component.

[0028]

Embedded image (N = integer of 2 to 4)

Polymers of these aromatic hydrocarbon fractions can be extracted and separated from cracked gasoline by a known method. For example, a polymer containing n = 2 four-ring aromatic hydrocarbons as a main component is Japan. Oil Co., Ltd. Hisol SAS-SH
Can be used.

The amount of addition is preferably 5 to 100 parts by weight of the isocyanate-terminated urethane prepolymer.
100 parts by weight, particularly preferably 30 to 60 parts by weight, are used. When the amount is less than 5 parts by weight, the bondable time under high temperature and high humidity is shortened, and when the amount is more than 100 parts by weight, the initial adhesive strength under low temperature and low humidity decreases, which is not practical.

When used as an adhesive, the curable urethane resin composition of the present invention may optionally contain an organic solvent, a plasticizer, an inorganic filler, a tackifying resin, a catalyst and the like depending on its use. .

As the organic solvent, toluene, xylene,
Hydrocarbon type represented by cyclohexane, 1,1,1
-Trichloroethane, ketones typified by carbon tetrachloride, and esters typified by ethyl acetate and ethyl propionate. These may be used alone or in combination of two or more, and are used as a viscosity modifier for the curable urethane resin composition.

Examples of the plasticizer include ester-based plasticizers such as dibutyl phthalate, dioctyl phthalate, dilauryl phthalate, butylbenzyl phthalate, diisodecyl phthalate, dibutyl adipate, dioctyl adipate, diisodecyl adipate, dioctyl azelate, dioctyl sebacate, and trioctyl sebacate. Examples thereof include phosphoric acid ester plasticizers such as octyl phosphate and triphenyl phosphate.

Examples of the inorganic fillers include clay, calcined clay, talc, silica, alumina, magnesium oxide, calcium silicate, asbestos, calcium aluminate, sodium aluminate, magnesium silicate, calcium hydroxide, barium sulfate, carbon black, Examples thereof include mica, titanium oxide, calcium carbonate, surface-treated calcium carbonate and the like. In particular, it is preferable to use the surface-treated calcium carbonate from the viewpoint of imparting thixotropic properties and economical aspects.

Examples of the tackifying resin include alkylphenol resins, terpene resins, terpenephenol resins, xyleneformaldehyde resins, rosins, hydrogenated rosins, coumarone resins, aliphatic and aromatic petroleum resins.

Examples of the catalyst include dibutyltin dilaurate, stannous octoate, polyethylenediamine and the like.

The curable urethane resin composition of the present invention is mainly used as an adhesive. For example, as a method of constructing a waterproof cushion sheet at a construction site, it is preferable to use concrete which has been subjected to surface treatment such as sanding. A curable urethane adhesive, preferably in an amount of about 0.3 kg / m ² , is applied to the substrate by a roller. Then, after taking an open time of 20 to 40 minutes and confirming the tackiness of the adhesive, a step of attaching a waterproof buffer sheet is performed.

[0038]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

Example 1 Liquid polybutadiene containing terminal hydroxyl groups (number average molecular weight of about 3)
000, trade name G-3000, manufactured by Nippon Soda Co., Ltd. 10
0 parts by weight, 18 parts by weight of polymethylene polyphenylisocyanate (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.), and 65 parts by weight of ethyl acetate and 65 parts by weight of toluene as solvents were charged into a reaction vessel, which was heated to 70 ° C. Was reacted for 5 hours. Then, the solid content of this prepolymer (hereinafter referred to as urethane prepolymer I) 10
To 0 part by weight, 10 parts by weight of a 4-ring aromatic hydrocarbon compound (a compound containing n = 2 in Chemical formula 1 as a main component) was added and mixed and stirred at the same temperature for 1 hour to give a free NCO group of 0.92.
A one-part moisture-curable urethane resin composition having a weight percentage of 50% and a non-volatile content of 50% was obtained.

Thereafter, a polymer of aromatic hydrocarbon fraction,
In Chemical formula 1, the compound name whose main component is n = m is (m +
2) Specify as a ring aromatic hydrocarbon.

The resin composition obtained was treated at low temperature and low humidity (5 ° C.).
* 20%), 0.3Kg / m ² on a slate plate, and after 20 minutes of open time, a waterproof cushioning sheet made of ethylene propylene rubber (trade name Tobus sheet, manufactured by Dainippon Ink and Chemicals, Inc.) Paste 1 hour later, 4 hours later, 1
The adhesive strength after 7 days was measured. Adhesive strength is represented by (g / inch) by adopting 90 ° peel test.

Example 2 A test was conducted in the same manner as in Example 1 except that the amount of the 4-ring aromatic hydrocarbon compound was changed to 40 parts by weight based on 100 parts by weight of the urethane prepolymer I.

Example 3 A test was conducted in the same manner as in Example 1 except that the amount of the 4-ring aromatic hydrocarbon compound was changed to 80 parts by weight based on 100 parts by weight of the urethane prepolymer I.

Example 4 A test was conducted in the same manner as in Example 1 except that the 4-ring aromatic hydrocarbon compound was changed to a 5-ring aromatic hydrocarbon compound based on 100 parts by weight of the urethane prepolymer I.

Example 5 Liquid polybutadiene having terminal hydroxyl groups (number average molecular weight of about 3)
000, trade name G-3000, manufactured by Nippon Soda Co., Ltd. 10
0 part by weight, 26.9 parts by weight of polymethylene polyphenylisocyanate (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 51 parts by weight of a 4-ring aromatic hydrocarbon compound were placed in a reaction vessel and heated to 70 ° C. 5
Allowed to react for hours. As a result, the viscosity is 8000 cps / 25
A urethane prepolymer II having a free NCO group of 3.1% by weight and a non-volatile content of 100% was obtained at ℃.

Next, polypropylene ether glycol (number average molecular weight 3200, Dainippon Ink and Chemicals, Inc.)
Made, Pandex OD-X-825) MOCA to 40 parts
After 4.5 parts were heated and dissolved, 2 parts of a 24% lead octylate solution was added to obtain a curing agent.

Example 1 100 parts by weight of the above urethane prepolymer II and 39 parts by weight of a curing agent were uniformly mixed by stirring.
The same test was carried out.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that the non-volatile content was changed to 50% without adding the 4-ring aromatic hydrocarbon compound.

Comparative Example 2 Example 2 was repeated except that a 3-ring aromatic hydrocarbon compound was used in place of the 4-ring aromatic hydrocarbon compound in Example 2.
The test was conducted in the same manner as in.

Comparative Example 3 A test was conducted in the same manner as in Example 2 except that a commercially available rosin ester was added in place of the 4-ring aromatic hydrocarbon compound in Example 2.

Comparative Example 4 In Example 2, instead of the 4-ring aromatic hydrocarbon compound, the temperature range of the melting start point and the melting point of the DSC chart was 1
The test was conducted in the same manner as in Example 2 except that a commercially available petroleum resin (Nisseki Liki Resin L30 manufactured by Nippon Oil Co., Ltd.) at 8.6 ° C. was added.

Comparative Example 5 In the prepolymer II of Example 5, the urethane prepolymer III containing no 4-ring aromatic hydrocarbon compound was used, the NCO / H ⁺ value was made the same, and the mixture was stirred and mixed with the curing agent. The test was conducted in the same manner as in Example 5.

The formulations and results of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1 above. In each of the examples, no aromatic hydrocarbon compound is added, that is, the initial adhesive strength is superior to that of Comparative Example 1. In Example 4, the adhesive strength was similar to that of the other Examples, but the softening point of the 5-ring aromatic hydrocarbon compound was around 80 ° C., and it was difficult to handle. Also,
When an aromatic hydrocarbon compound having a low softening point as in Comparative Example 2 was used, the initial adhesiveness and the adhesive strength after 7 days (hereinafter, the final adhesive strength) tended to be remarkably poor. The final adhesive strength of a general-purpose tackifying resin such as rosin ester of Comparative Example 3 was lower than that of Comparative Example 1. The softening point of Comparative Example 4 was 4
When a petroleum resin having the same melting start point and melting point temperature range of DSC as the cyclic aromatic hydrocarbon compound was used, the initial adhesiveness and the final adhesive strength were poor. From Example 5 and Comparative Example 5, similar results were confirmed in the two-component curable type.

[0054]

[Table 1] -The composition is shown in parts by weight and the adhesive strength is shown in g / inch.

The n-ring system in the table represents an n-ring aromatic hydrocarbon compound, and (Mp-Ms) represents the melting start point and melting point temperature range of the DSC chart.・ The * in the table indicates that the rubber sheet was broken when the adhesive strength was 5000 g / inch or more.

Examples 6 to 10 Example 1 to Example 10 were repeated except that the adhesion test was conducted under high temperature and high humidity (40 ° C. * 80%) with an open time of 90 minutes.
The same test as in Example 5 was performed.

Comparative Examples 6 and 7 The same tests as in Comparative Examples 1 and 5 were performed, except that the adhesive test was conducted under high temperature and high humidity (40 ° C. * 80%) with an open time of 90 minutes.

The results of Examples 6 to 10 and Comparative Examples 6 and 7 are shown in Table 2 above. In each of the examples, even when the open time was long under high temperature and high humidity, the initial adhesive strength was not decreased and the final adhesive strength was maintained.

[0059]

[Table 2] -The composition is shown in parts by weight and the adhesive strength is shown in g / inch.

The n-ring system in the table represents an n-ring aromatic hydrocarbon compound, and (Mp-Ms) represents the temperature range of the melting start point and melting point of the DSC chart.・ The * in the table indicates that the rubber sheet was broken when the adhesive strength was 5000 g / inch or more.

The curable urethane resin compositions of the examples according to the present invention maintain the final adhesive strength as compared with the comparative examples, have a shorter time of developing tackiness at low temperature and low humidity, and can be adhered at high temperature and high humidity. The time was long, that is, the final adhesion and tack properties were excellent.

[0062]

INDUSTRIAL APPLICABILITY The present invention includes a compound having a temperature difference between a specific melting point and a melting start point in DSC, so that when it is used as an adhesive, the final adhesive strength of the adhesive is maintained, The adhesive property and the final adhesiveness are excellent in that the time for developing the tackiness at low temperature and low humidity can be shortened and the time for adhering at high temperature and high humidity can be extended. In particular, it is useful as an adhesive used for construction of waterproof cushioning urethane sheets at construction sites, and can be used as an all-season type adhesive whose open time is less affected by the external environment at construction sites.

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Claims (8)

[Claims] 1. A curable urethane resin composition comprising a compound in which the difference between the melting start temperature and the melting point of the chart measured by a differential scanning calorimeter is within 15 ° C. 2. The curable urethane resin composition according to claim 1, wherein the softening point of the compound is 20 ° C. or higher. 3. The melting point of the compound is 30 to 150 ° C.
The melting point is 35 to 165 ° C., and the curable urethane resin composition according to claim 1. 4. The curable urethane resin composition according to claim 1, wherein the compound is an aromatic hydrocarbon compound. 5. The aromatic hydrocarbon compound is C _{8 to} C ₁₀
The curable urethane resin composition according to claim 4, which is a polymer of an aromatic hydrocarbon fraction. 6. The curable urethane resin composition according to claim 1, which is a one-pack moisture-curable type. 7. The curable urethane resin composition according to claim 4, wherein the aromatic hydrocarbon compound contains a polymer represented by Chemical formula 1 as a main component. Embedded image (N = integer of 2 to 4) 8. An adhesive comprising the curable urethane resin composition according to claim 1.