JPS60120750A - Thixotropic polyurethane composition - Google Patents

Abstract

PURPOSE:To provide a compsn. having thixotropic properties without lowering storage stability, workability such as blending, or application, by incorporating a polyurethane resin with a urea deriv. and colloidal silica. CONSTITUTION:0.1-20pts.wt. urea deriv. (e.g., tetramethylurea) (B) and 0.1- 50pts.wt. colloidal silica (C) are incorporated with 100pts.wt. polyurethane resin (A) to yield the titled compsn. So far, it has been proposed that by incorporating component C into component A, thixotropic properties are imported and sagging during application is prevented. However, an increase in the amount of anti-sag agent has a defect that the viscosity of resin is increased and workability is lowered, and also tends to increase the hardness and modulus and decrease the elongation and adhesion. By further adding component B, proper thixotropic properties are imparted and other properties required for polyurethane, such as workability during blending and application, are maintained sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rice-based polyurethane composition, and more specifically, by blending a specific amount of a urea derivative and colloidal silica into a polyurethane resin, the composition improves storage stability, mixing, construction, etc. pJJ is added to the rice and wheat polyurethane composition that imparts rice and wheat properties without reducing properties.

Because polyurethane has excellent properties such as rubber elasticity, weather resistance, and abrasion resistance, it is used as a coating material for elastomers, paper, and cloth, as well as construction materials such as paints, sealants, adhesives, flooring materials, and wall materials, as well as civil engineering materials. It is used in a wide range of fields such as interest.

This polyurethane application generally consists of a polyurethane prepolymer in liquid or solution form! - or liquid compositions are used, and various compounding agents such as fillers such as talc and carbon black, plasticizers, adhesives (JJj agents, curing catalysts, coloring agents, etc.) are added to this. Depending on the method, it is broadly divided into two-component types, such as one-component polyurethanes, which have one or more isocyanate groups at the end of the urethane prepolymer and are cured by moisture, etc., which are popular after application, and two-component polyurethanes, which are cured with polyols. Depending on its use, rice and wheat characteristics (thixo 1 to
For example, when applying polyurethane vertically as a paint or sealant, it is difficult to sag due to the long brushing and spatula handling, resulting in a beautiful finish. Further, when applied as an adhesive or coating material to C porous paper or cloth, there is an advantage that there is little seepage and the application operation is easy.

As a way to improve the properties of this polyurethane and prevent sag during construction, it has been proposed to add sag-preventing agents such as colloidal silica and bentonite. However, as the amount of anti-sagging agents such as colloidal silica is increased, the thixotropy improves and the sagging phenomenon is suppressed, but the apparent viscosity of polyurethane increases significantly, making work such as mixing and construction difficult. The disadvantage is that it worsens
Furthermore, the physical properties after curing (C) increase in hardness and modulus, and decrease in extensibility and adhesiveness, so they have various properties that are required for building materials and civil engineering materials such as sealants, adhesives, and coating materials. I can't be satisfied.

Various methods have been proposed for imparting thixotropy without impairing other properties. For example, (1) a polyurethane composition in which a polyurethane polymer is mixed with polyethylene glycol or its derivative and colloidal silica in a specified amount (Japanese Patent Publication No. 45-41110), (2) a liquid polyurethane having an isocyanate-1 group at the end, an inorganic filler, Polyurethane compositions containing oxyalkylene compounds etc. (Japanese Patent Publication No. 47-7632); ■Production method for urethane sealants in which polyurethane raw materials are blended with specific anti-sagging agents such as sulfoxides (Japanese Patent Publication No. 49-1986) No. 27418), etc. However, even with these methods, sufficient thixotropy is still not imparted, and the problem of poor workability during mixing and construction due to changes in thixotropy during storage and increased apparent viscosity has been sufficiently resolved. It has not been done.

The present invention was made to solve the above-mentioned drawbacks of the prior art, and it provides sufficient thixotropy without reducing storage stability, workability in mixing, construction, etc., and also has heat resistance, weather resistance, The purpose of this invention is to provide a thixotropic polyurethane composition with excellent cold resistance, which is particularly used in sealants, fillers, adhesives, etc.

As a result of intensive studies in line with the above objectives, the present inventors identified urea derivatives and colloidal silica for polyurethane resin.
The present inventors have discovered that by dispersing polyurethane, sufficient thixotropy can be imparted to polyurethane, and other properties required of polyurethane, such as processability during mixing and construction, can also be sufficiently maintained.

Accordingly, the present invention uses urea derivatives of 0.1 to 100 parts of polyurethane resin (polyurethane prepolymer).
This is a thixotropic polyurethane composition characterized by containing ~20 parts by weight and 0.1 to 50 parts by weight of colloidal silica.

As the polyurethane resin (polyurethane prepolymer) used in the present invention, in the case of -wave type, a polyurethane prepolymer having terminal isocyanate groups is used. This prepolymer is produced by reacting a polyether polyol such as polyoxypropylene diol or triol, or other polyol having an average molecular weight of about 11,000 to 1000, which has a hydroxyl group at the end, with a polyisocyanate. As the polyisocyanates, 1-herylene diisocyanate (TD), 4,4'-diphenylmethane diisocyanate (MDI), and others alone or in combination, or modified ones can be used. −
In the case of liquid polyurethane, the terminal isocyanate 1-groups of the prepolymer react with moisture in the atmosphere to form giant molecules or network molecules. This forms the main structure of the polyurethane, which is characterized by elasticity.

The base polymer for two-component polyurethane is
One component is a prepolymer with terminal isocyanate groups similar to the above-mentioned liquid polyurethane, and the average molecular weight is m 1ooo ~
The other component is usually a polyol having about 5,000 terminal hydroxyl groups. As the polyol, polyoxypropylene diol, polyA-xypropylene tri-A-l, or a copolymer thereof with ethylene oxide is often used, but other polyols may also be used. For two-component polyurethane, the prepolymer component and polyol component are mixed just before construction. The reaction mainly involves the bonding of the terminal groups of both components, that is, the urethane bonds, and can be cured independently of moisture.

These polyurethane resins are originally liquid, or they are dissolved in a solvent to form a liquid. Examples of the solvent used here include esters such as ethyl acetate, ketones such as methyl ethyl ketone, and aromatic hydrocarbons such as 1-toluene.

The urea derivatives blended in the present invention include, for example, tetramethylurea, tetramethylurea, L3-dimethyl-2-imidazolitone, etc., and each urea group has a molecular weight of 1100
Compounds within 0 are preferred. The blending amount of the urea derivative is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polyurethane resin. If the amount m of the urea derivative is less than 0.1 part by weight, the desired rice properties cannot be obtained and the sagging prevention effect is insufficient, and if it exceeds 20 parts by weight, storage stability and workability will deteriorate. .

Commercially available silica compounded in the present invention can be appropriately used, such as Aerosil. The amount of colloidal silica to be blended is 0.1 to 50 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the polyurethane resin. If the amount of colloidal silica is less than 0.111 parts, the rice properties and prevention of sagging will be insufficient, and if it exceeds 50 parts by weight, storage stability and workability will deteriorate.

In the present invention, when a urea derivative and colloidal silica are combined in a polyurethane resin, hydrogen bonding between silanol groups of the colloidal silica is promoted to form a continuous structure.

This structure is easily destroyed by a weak external force, and the viscosity temporarily decreases, but when the external force is removed, a continuous structure is restored. Therefore, the polyurethane composition of the present invention has good fluidity during mixing and application, making it possible to apply the desired shape to the desired area, and after the work is finished, the apparent high viscosity suppresses the sagging phenomenon. .

In the polyurethane composition of the present invention, in addition to these essential components, a -C1 filler, a plasticizer, a curing accelerator, an adhesion imparting agent, a curing catalyst, a coloring agent, etc. can also be blended as appropriate.

Hereinafter, the present invention will be explained in detail based on Examples and Comparative Examples.

- Examples 1 to 3 and Example 1 Polyoxypropylene triol 56 with a molecular weight of 5000
Polyoxypropyle glycol 44 molecule 1 2000, 20 m ffi
After putting part into a reaction vessel and dehydrating under reduced pressure at 100°C,
It was cooled to 80° C. under nitrogen gas. While stirring, add 4.4'-diphenylmethane diisocyanate (MD
20 parts of I) were added, and 1 to 2 parts of N11 isocyanate were added.
．． The reaction was carried out until the concentration reached 54%, and a urethane prepolymer was prepared.

The obtained urethane prepolymer, inorganic filler, plasticizer, etc. were added in the mixing ratio shown in Table 1 into a mixing stirrer filled with dry nitrogen gas, and the mixture was stirred and kneaded at room temperature to form a paste-like polyurethane composition. was prepared.

This polyurethane composition conforms to JIS A 5758191.
A slump test was conducted according to the slump test method for sealing materials for construction under No. 9, and samples with a thickness of 0 to 1 mm were considered to have rice-wheat properties, and those with a thickness of 11 or more were considered to have rice-wheat properties.

The slump test results are shown in Table 1 along with the amounts of each compounding agent.

Table 1 As is clear from the results in Table 1, the polyurethane compositions (Examples 1 to 3) in which a urea derivative and colloidal silica were blended together in a polyurethane resin were different from those in which a urea derivative was blended in a polyurethane resin. First, it can be seen that the composition is superior in terms of graininess compared to the polyurethane composition containing colloidal silica (Comparative Example 1).

Examples 4 to 6 and Comparative Example 2 Using the urethane prepolymer prepared in Example 1,
Urethane prepolymer, filler, plasticizer, etc. were added in the mixing ratio shown in Table 2 into a 11' mixer with dry nitrogen gas, and the mixture was stirred and kneaded at air temperature. A pasty polyurethane composition was prepared.

Slump test of this polyurethane composition is shown in Example 1.
The results are shown in Table 2 along with each compounding agent.

Table 2 As is clear from this Table 2, the polyurethane resin obtained by varying colloidal silica and urea M conductor within the sun of the present invention [acid (Example 1 rows 4 to 6)] exhibits thixotropy. However, the polyurethane composition (Comparative Example 2) in which the polyurethane resin was not blended with co-L'oidal silica and was blended with the urine M derivative (Comparative Example 2) did not have thixotropy.

As explained above, the polyurethane composition of the present invention, which contains a polyurethane resin in combination with a urea derivative and colloidal silica, has good thixotropy, storage stability, and processability during mixing and construction. In addition to these properties, it also has excellent heat resistance, weather resistance, and cold resistance, so it strongly adheres to base materials such as primer-treated metal, concrete, mortar, wood, and plastic. Effectively used for sealing materials, sealing materials, adhesives, etc.

Patent applicant: Yokohama Rubber Co., Ltd. Agent: Patent attorney Tatsuo Ito Agent: Patent Attorney Tetsuya Ito

Claims (1)

[Claims] 1. For 100 mm parts of polyurethane resin, 0.1 to 20 parts by weight of urea derivative, 0.1 to 50 tons of colloidal silica
A rice-based polyurethane composition characterized by containing a Jm part.