JPH03215554A - Thixotropic polyurethane resin composition - Google Patents

Abstract

PURPOSE:To obtain a moisture-curing polyurethane resin composition being nonproblematic in storage stability, adhesiveness, resin strength and carcinogenicity, showing stable thixotropy and being useful as an adhesive, a sealing agent or the like by dispersing sepiolite in an active NCO-containing urethane prepolymer. CONSTITUTION:0.5-5wt.%, desirably 0.8-3.0wt.%, based on the total weight of the composition, sepiolite (desirably one predried to a water content of 2% or less) is dispersed in an active NCO-containing urethane prepolymer, e.g. one based on a polymer obtained by reacting a polyether polyol of a mol.wt. of 3000 with an excess of MDI in an NCO to OH ratio of 6 and having an NCO content of 9.3wt.% and a viscosity of 8000cP at 25 deg.C to obtain a thixotropic polyurethane composition (of a ratio of the viscosity at 2rpm to that at 20rpm of 3-5).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thixotropic polyurethane resin composition, more specifically, a thixotropic polyurethane resin composition containing a urethane prepolymer containing an active isonoanate group as a main component, which is useful as an adhesive or a knolling material, and is particularly useful for wall surfaces. The present invention relates to a moisture-curable polyurethane resin composition that does not cause tiles to slip or fall due to its excellent thixotropy when used for tiling such as tiles.

Problems to be Solved by the Prior Art and the Invention Urethane prepolymers containing active isonoanate groups exhibit moisture curability;
Polyurethane resin compositions that react with moisture in the air to form a cured film, and whose main component is this polyurethane polymer, are used as adhesives and sealants.

However, when this composition is used, for example, for tiling a wall surface, a problem arises in which the tiles shift and fall, and attempts have been made to impart thixotropy to prevent this problem. Generally, a thixotropic agent is used for this, and one or a combination of two or more of them, such as finely powdered silica, noricone wax, or amide wax, is added.
Addition of fine powder adhesive reduces storage stability, and addition of noricorn-based or amide-based waxes impairs tile adhesion when adhesive is applied, and reduces resin hardening after curing. However, the L problem arises, and there are restrictions on their use. In addition to these, techniques for imparting thixotropy by adding fibrous substances such as asbestos have been known for a long time, but they cannot currently be used due to the carcinogenicity of asbestos.

On the other hand, a thixotropic polyurethane resin is designed to exhibit thixotropy and to stabilize the thixotropy over time by combining two types of urethane prepolymers containing active isocyanate groups that are incompatible with each other as main components. A composition has been devised (see Japanese Patent Application Laid-open No. 1132662). However, even with this composition, due to the reactivity of the main component resin itself and its viscous nature due to its high molecular weight of several thousand, it is difficult to use epoxy resin, which is commonly used for adhesion of tiles on vertical surfaces and in so-called thixotropic adhesives. Compared to resin etc.
The thixotropic effect was insufficient.

As a means to solve the problem, the present inventors conducted intensive studies on imparting thixotropy, and found that a specific amount of sepiolite (SEP IOL I TB), which is one of the clay minerals, was added to the thixotropy. If used in place of a modifier, the above-mentioned problems with storage stability, adhesive strength, resin strength, and carcinogenicity will be solved, and it will also have excellent thixotropic effects, such as the rotational speed in a B-type viscometer. 2
The inventors have discovered that a stable thixotropic property with a ratio of viscosity at rpm/viscosity at rotational speed of 20 rpm of 3 to 5 is exhibited, and have completed the present invention.

That is, the present invention has an active isocyanate group-containing urethane prepolymer (hereinafter referred to as an NCO-containing prepolymer) as a main component, and 0.5 to 5% (weight %, hereinafter the same) of sepiolite based on the total amount of the composition is added and dispersed. The present invention provides a thixotropic polyurethane resin composition characterized by the following.

The NGO-containing prepolymer in the present invention is prepared by combining a polyether polyol and/or a polyester polyol with an excess of a polyisocyanate compound, i.e., a polyisonene I
・The active i-nonanoate group (NCo) of the compound is more than 1: ), for example, 1 3≦NGO/OH≦1
It is produced by reacting at 70 to 100°C for several hours at a ratio of 0 to 100%, and the NGO content is usually adjusted to 1 to 15%. In this reaction, a conventional catalyst, plasticizer or solvent may be used.

Master. As the self-polyether, for example, a low molecular weight active hydrogen compound having two or more active hydrogen atoms (
For example, ethylene glycol, propylene glycol,
Butylene glycol, diols such as 1,6-hexanediol, glycerin, trimethylolpropane, 1
Propylene oxide and ethylene oxide are subjected to ring-opening polymerization in the presence of one or more of triols such as 2.6-hexanetriol, ammonia, amines such as methylamine, ethylamine, probylamine, and butylamine). polyoxypropylene polyol (especially preferred is ethylene oxide or 30 mol% or less of polyethylene), or a polyoxypropylene polyol obtained by ring-opening polymerization of Te1-rahytrofuran. Examples include tetramethylene glycol, which usually has a molecular weight of 300 to 7,000 and an OI content of 2 to 4 per molecule.

Polyester polyols used in place of or in combination with the above polyether polyols include, for example, aromatic polybasic acids (phthalic acid, terephthalic acid, isophthalic acid, or noalkyl esters thereof, etc.) and polyhydric alcohols. (In addition to the diols and 1-liols mentioned above, it also includes noethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol), and usually has a molecular weight of 300 to 3000. , has 2 to 4 OH-containing M atoms in one molecule.

Examples of the above-mentioned polyisonoane compounds include aliphatic polyisonoanates such as hexamethylene diisoanate and lysine methyl ester diisocyanate;
Alicyclic polyisocyanates such as hydrogenated nophenylmethane diisonoanate, isophorone noisonoanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate (TDI), nophenylmethane noisocyanate (M
DI), aromatic isocyanates such as naphthylene diisocyanate, xylylene noisonoanate, and mixtures thereof. Particularly preferred polyisonoanate compounds are aromatic polyisocyanates, such as TD L MD I and the like.

The sepiolite in the present invention has the structural formula S ilFMg8030(OH)4(OH2)4, which is mainly composed of hydrated magnesium silicate.
・A fibrous mineral represented by 8 H20, generally 1
It has a fiber length of 2.7 cm, and its distribution range is 0 to 0.
1-12.7m. It is preferable that the water content be adjusted to 2% or less by drying in advance.

The amount used is 0.5 to 5% based on the total amount of the composition, preferably 0.
Select in the range of 8 to 30%. If it is less than 0.5%, the desired thixotropic effect cannot be obtained, and if it exceeds 5%, the viscosity becomes high and workability deteriorates.

The thixotropic polyurethane resin composition according to the present invention has the above-mentioned N
The system consists of a GO-containing prepolymer as the main component, with a predetermined amount of sepiolite added and dispersed therein, and if necessary, ordinary fillers (carnoum carbonate, talc, clay, metal powder, carbon blanker, etc.) , a small amount of thixotropic agent (@
Powder glue, bentonai}, etc.), curing accelerators, adhesives, etc. may be added.

The composition of the present invention has a stable viscosity ratio of 3 to 5 and has a 1-thickness property, and the use of sepiolite has no carcinogenicity or any problem, and is equivalent to asbestos. The resin reinforcement effect is recognized.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1.2 and Comparative Example 1.2 (1) NGO impregnated prepolymer (A) NGO,
/0 1. ．． Add excessive MDI so that it becomes { or 6,
Reacted at 90°C for 5 hours, NGO content 9.3%
, an NCO-containing prepolymer with a viscosity (20° C.) of 8 0 0 0 cps (BH type, rotor No. 6, 2 O rpm) is obtained.

(2) NGO-containing prebolimer (B) Min-F4t2000 polyester polyol (Asahi?t
Manufactured by T Kachogyo (Aji), Adeka Polyester F'7-67)
i: N.C. Add excess MDI to make O/OH 6, react at 90'C for 5 hours, and NG
O content: 0.2%, viscosity (20°C): 2.5 0.0
0 cps (BH type, [litter No. 6, 2 O rp
Obtain the NGO-containing prepolymer of m).

(3) Polyurethane resin composition - The components shown in Table 1 are stirred and mixed to obtain a polyurethane resin composition.

Viscosity change of the hot composition (20'C, rotor No. 7,
The results are shown in Table 1.

Adhesive was applied to the vertical mortar surface using a comb trowel, and ceramic tiles (9 8 x 9 8 mm) were adhered (7. The tile was observed for shear and fall until the adhesive hardened.

Table 1 (B) 20 carbonated power runum 100 100 100 ]00 100 Fine powder Norica 2 1 sepiolite 2 4 3 1 Viscosity [y ratio 4 2 50 48 32 3.5 Hanging length (mF) 3 0 0 30 note) In the table, ○ means no slipping or falling

Claims (1)

[Scope of Claims] 1. A thixotropic polyurethane resin composition characterized in that the main component is a urethane prepolymer containing active isocyanate groups, and 0.5 to 5% by weight of sepiolite based on the total amount of the composition is added and dispersed therein. . 2. The thixotropic polyurethane resin composition according to claim 1, wherein the sepiolite is previously dried to a moisture content of 2% or less. 3. The thixotropic polyurethane resin composition according to claim 1, having a ratio of viscosity at a rotational speed of 2 rpm/viscosity at a rotational speed of 20 rpm = 3 to 5.