JPS61275324A - Heat-curable polyurethane composition - Google Patents

Abstract

PURPOSE:The titled composition excellent in storage stability and useful as a sealing material or an adhesive, comprising an organic polyisocyanate, etc., and a solid polyhydroxy compound powder surface-coated with a wax. CONSTITUTION:An isocyanate-terminated prepolymer, viscosity of 100-100,000cP, obtained by reacting an aromatic, aliphatic or alicyclic organic polyisocyanate compound having at least two isocyanate groups or a combina tion of this compound with a polyol of a MW of 60-8,000 at room temperature - 120 deg.C so that free isocyanate groups may remain is mixed with a polyhydroxy compound [e.g., 1,4-di(beta-hydroxyethoxy)phenol] in such an amount as to provide an OH group/NCO group ratio of 2.5-0.5 (equivalent weight) and, optionally, 1-10wt% water binding agent such as a molecular sieve or CaO and a silicone coupler.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a heat-curable polyurethane composition industrially useful as a sealant or adhesive (Prior Art) According to JP-A-58-120627 , discloses a polyurethane composition comprising a liquid aromatic prepolymer and a solid polyhydroxy compound. This composition was heated to 149°C.
It is a heat-curable one-component polyurethane adhesive composition that cures when heated to a temperature of 100 mL and has various properties suitable for assembling automobile parts.

However, conventional one-component polyurethane adhesives have low storage stability in closed containers and have a curing temperature of 1%.
Problems have been pointed out, such as the need for high temperatures of 50°C or higher.

(Problems to be Solved by the Invention) Storage stability in a closed container is an important performance for adhesives and sealants of this type, and its merits and demerits determine the commercial value in the market. Since the curing temperature is used for assembling automobiles, it is desired that the curing temperature is below the heat resistance temperature of plastics, that is, 120 to 150°C. It goes without saying that low temperatures are preferable from the point of view of energy and resource conservation.

(Means for Solving the Problem) As a result of various studies, the present inventors have found that by coating the surface of a finely ground polyhydroxy compound with wax, the curing temperature is lowered and the storage stability is significantly improved. The present invention has made it possible to do so. That is, the present invention comprises (11(a) an organic polyisocyanate compound or a prepolymer having an isocyanate group as a terminal group, and (b) a polyhydroxy compound having two or more active hydrogen atoms in each molecule whose surface is coated with wax. A thermosetting polyurethane composition comprising a solid powder and having an equivalent ratio of active hydrogen to isocyanate groups of 2.5 to 0.5.

(2) (a) an organic polyisocyanate compound or a prepolymer having isocyanate groups as terminal groups;
It consists of a solid powder of a polyhydroxy compound having two or more active hydrogen atoms per molecule, whose surface is coated with bJ wax, and the equivalent ratio of active hydrogen to isocyanate groups is 2.
A heat-curable polyurethane composition characterized in that a silicone coupler is further added to the composition having a polyurethane content of 5 to 0.5, or the composition is reacted with an isocyanate group as necessary. The organic polyisocyanate compound used in the present invention has about 2 isocyanate groups.
Aromatic, aliphatic, or alicyclic having one or more aromatic, aliphatic, or alicyclic compounds, which can be used alone or as a mixture. For example, tolylene diisocyanate (including various mixtures of isomers)
(TDI), diphenylmethane diisocyanate (including mixtures of isomers) (MDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TO
DI), 1,4-phenylene diisocyanate (PDI)
), xylylene diisocyanate (XDI)stetramethylxylylene diisocyanate (TMXDI),
naphthylene diisocyanate (NDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MD
I) % crude TDI, polymethylene polyphenylisonate (crude fiMDI), inphorone diisocyanate (IPDI), hexamethylene diisocyanate (
HDI), hydrogenated xylylene diisocyanate (HXD)
In addition to I), these isocyanates include incyanure-(tt) ratio modified products, carbodiimidized modified products, biuret modified products, and the like. In particular, it is preferable to use all the aromatic polyisocyanate compounds singly or as a mixture.

The terminal isocyanate group greborimer used in the present invention is obtained by reacting the above-mentioned various organic polyisocyanate compounds with a known polyol by a known method so that free isocyanate groups remain.

The polyol used here is a compound having two or more hydroxyl groups. Polyether polyols obtained by addition polymerization of oxide or propylene oxide and ethylene oxide, ethylene glycol, propylene glycol and their oligoglycols, butylene glycol, hexylene glycol, polytetramethylene ether glycols,
Polymers obtained by grafting vinyl monomers onto polycaprolactone polyols, polyester polyols such as polyethylene adipate, polybutadiene polyols, esters of higher fatty acids containing hydroxyl groups such as castor oil, polyether polyols, or polyester polyols.・It is a polyol.

The preferred molecular weight range of these polyols is 60 to
s, ooo. When reacting an organic polyisocyanate compound and a polyol to form a prepolymer,
The reaction is carried out in a conventional manner, that is, at room temperature to 120°C. The ratio of organic polyisocyanate to polyol may be about 1.2 to 3.5 in terms of equivalent ratio. Further, the NC0% of the prepolymer is 1 to 35% by weight. The viscosity of the obtained prepolymer ranges from 100 to 100,000 from the point of view of compounding operations.
A range of 0 centivoise is preferred, and for that purpose plasticizers,
The polyhydroxy compound having two or more active hydrogens in one molecule used in the present invention is preferably a polyhydroxy compound, and it is preferable to For example, ingropylidene bis(β-hydroxyethoxyphenol) (a compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol A (BPA・2EO), 1,4-di(β-hydroxyethoxy)phenol (hydroquinophenol), Compound s HQ@2 with 2 moles of ethylene oxide added to 71 moles
EO), pentaerythritol, dipentaerythritol, tripentaerythritol and mixtures thereof,
The waxes used in the present invention, such as neopentyl glycol [2゜2-bis(hydroxymethyl)1.3propanediol], include petroleum waxes, polyethylene waxes, natural waxes, oxidized waxes, and synthetic waxes. Among these, the melting point is 60-120℃
Preferably. If the melting point is too high, exceeding this range, the curing temperature will become high; if it is too low, the storage stability will deteriorate.

The amount of wax coating is 3% of the polyhydroxy compound.
~30% by weight is preferred. If the amount exceeds this amount, the adhesiveness of the polyurethane composition will decrease, and if the amount is less than this amount, the storage stability will deteriorate.

To produce the heat-curable polyurethane composition of the present invention, the surface of the finely pulverized polyhydroxy compound is coated with wax using a device such as a CF-granulation coating device, 5PIR-A-FLOW, or a counter jet mill. This and a prepolymer having terminal isocyanate groups are blended so that the equivalent ratio of hydroxy groups/isocyanate groups is 2.5 to 0.5. In this case, if it exceeds 2.5 or less than 0.5, the required physical properties after curing will not be sufficiently developed. In this case, the percentage of plasticizer is O to the total amount of the composition.
Add 30% by weight. Plasticizers are added to reduce viscosity and facilitate workability.

The plasticizers used include di-2-ethylhexyl phthalate (DOP), diptyl phthalate (DBP), diisodecyl heptathalate (DIDP), di-2-ethylhexyl adipate (DOA), and tricresyl phosphate (TC).
In addition, molecular sheep, calcium oxide, or activated alumina is added in an amount of 1 to 10% by weight based on the total amount of the composition as an intersystem water binder.

If necessary, a silicone coupler is superimposed in 0.1 to 5 times the total amount of the composition. A Dalton mixer is used as a compounding machine, and the mixture is mixed for 1 hour at room temperature and defoamed to obtain a product. The silicone-based ingredients 2- include r-glycidoxyglobyltrimethoxysilane (A-187), sr-mercaptopropyltrimethoxysilane (A-189), or r-aminopropyltrimethoxysilane (A-110).
0) A product manufactured by Mounion Carbide Co., Ltd.] is suitable.1 The silicone coupler used here depends on the reactivity of the NGO group present in the reaction system, reaction conditions, etc.
It is also possible for both to react with each other in advance.

By heating the product to 60-120°C, the temperature will be about 10-3
Hardens in 0 minutes.

(Example) Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 The surface of 1 kg of finely ground HQ-2E0 was coated with Panfin Wax 155P (melting point 68.3 to 71.0°C) using a counter jet mill. The adhesion amount is 10
It was 0g. This was designated as A-1.

In a 3-ton four-eye flask equipped with an inlet, a nitrogen inlet, a stirrer, and a thermometer, under a nitrogen stream, the molecular weight was 1.50.
1.500 (1 mol) of a propylene oxide adduct of glycerin (MN-1500 manufactured by Mitsui Nisso Urethane) was added thereto, and the internal temperature was maintained at 45°C. Next, 1,500 g of M, which had been kept in liquid form at 45°C in advance,
DI (6 mol) was added, and the reaction was carried out for 2 hours while keeping the internal temperature at 80° C. while being careful of heat generation due to the reaction. NGO weight %: 12.5, viscosity 7.000 cps/25°C
Prepoly-r-(Pre-1) was obtained.

For 5t Dalton mixer (Pre-1) 1.000
t (2,976 equivalents), (A-1) 327t (3,0
03 equivalent), diisodecyl phthalate 150? , Molekier Sheeps 3A (manufactured by Union Carbide) 50ff
After charging and mixing for about 1 hour at room temperature, product I was obtained after defoaming.

Product I did not gel at 50° C. for 4 weeks and showed good storage stability.

Example 2 In the final blending step of Example 1, 7 t of r-glycidoxyprobyltrimethoxysilane was added and blended in the same manner as above to obtain product (1). Product (1) did not gel at 50° C. for 4 weeks and showed good storage stability.

Example 3 Micro-
Wax 180M (melting point 82.1-87.8°C) was coated with a counter jet mill.

The amount of adhesion was 103 tons. This was designated as A-2.

The sample obtained in Example 1 (Pre-
1) 1.000f (2,976 equivalent)s (A-2
) 亨′ 470? (3 equivalents), diisoferosyl phthalate 200t1
Molecular Sheeps 3A 50 f s r-chrysidoxyglobylmethoxysilane 5f was added, mixed at room temperature for about 1 hour, and after defoaming, product I was obtained.

Product ■ did not gel for 4 weeks at 50°C and showed excellent storage stability.

Comparative Example 1 In Example 1, finely ground HQ was substituted for A-1.
-2E0297 f (3,00 equivalents) was produced in the same manner, and the product (■) was obtained.

Comparative Example 2 In Example 1, 102 t (3,00 equivalents) of finely pulverized retapentaerythritol was used in place of A-1, and the same procedure was repeated except for the following to obtain product (1). Example 1. Example 2 and Example 3 are for Comparative Example 1.

It exhibited good storage stability. In addition, compared to Comparative Example 2, it exhibited low adhesive strength, curing temperature, and good storage stability. Adhesive strength showed the same or better results than the comparative examples, but in particular, Examples 2 and 3 using a 7-run coupler! Excellent adhesive retention after boiling□

Claims (2)

[Claims] (1) (a) an organic polyisocyanate compound or a prepolymer having isocyanate groups as terminal groups; and (b)
A heat-curable polyurethane consisting of a solid powder of a polyhydroxy compound having two or more active hydrogen atoms per molecule and whose surface is coated with wax, and the equivalent ratio of active hydrogen to isocyanate groups is from 2.5 to 0.5. Composition. (2) Consisting of (a) an organic polyisocyanate compound or a prepolymer with isocyanate groups as terminal groups, and (b) a solid powder of a polyhydroxy compound having two or more active hydrogen atoms in each molecule, whose surface is coated with wax. , a composition in which the equivalent ratio of active hydrogen to isocyanate groups is from 2.5 to 0.5, and a silicone coupler
1. A heat-curable polyurethane composition, characterized in that it is added with or reacted with an isocyanate group in advance as necessary.