JPS581748A - Silicone sealing material for civil engineering and building - Google Patents

Abstract

PURPOSE:To provide the titled sealing material which does not form darkish stain along joints after filling and has excellent waterproofness, electrical insulating properties, adhesiveness, elasticity, etc., by blending lamellar mineral powder and a hardener with a silicone rubber base material. CONSTITUTION:As lamellar mineral powder, particulate cleaved sericite or mica (pref. powder having an aspect ratio of 100 or above and consisting of at least 90% particles having a particle size of 6mu or below) is used. 100pts.wt. silicone rubber base material, 15-20pts.wt. lamellar mineral powder and a hardener are kneaded together to obtain silicone sealing material for civil engineering and building.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silicone sealant for construction and civil engineering that is filled into the joints of external walls such as PC structures and curtain wall structures.

The demand for cooling materials in construction has been rapidly increasing in recent years, especially for their excellent fatigue resistance and weather resistance, as well as their resistance to inter-story displacement during earthquakes in curtain walls of GPC (granite PC) and tile PC. In order to follow suit, 7 silicone sealing material was recognized as a sealing material, and demand continued to increase, reaching 4,800 tons per year in 1980. When silicone sealant is filled in the joints of external walls of PC structures, curtain wall construction, etc., depending on the type of exterior material, about 6 months to 2 years after filling,
Pale black contamination occurs, and this stretches in a strip along the joint, and its width is several meters or more. This contamination is noticeable in expensive stones, which are preferred as maintenance-free yet heavy exterior materials, and although it significantly impairs the aesthetics, there are currently no pre- and post-measures. It has become a big problem.

Regarding the causes of exterior contamination of silicone sealants,
For example, in the monthly magazine "Architectural Technology and Construction" August 1980 special issue, pages 92-93, "Contamination of exterior materials by sealants" (authors Tadashi Ono and Hiroshi Matsumoto),
Silicone was detected in this contaminated area by infrared spectroscopy, and this is because a small amount of low-molecular-weight silicone contained in the silicone sealant migrates to the exterior material, causing the area to exhibit a water-repellent effect. It is said that dust can adhere to the surface and cause it to become dark and dirty. 7 Silicone sealants come in two-component and two-component types, but both contain low-molecular-weight silicone that can cause contamination. The types of exterior materials where contamination is a problem include:
Based on the fact-finding survey, we found that stone, exterior tiles, patterned spray materials, painting,
It has been reported that metal curtain walls, etc.

Since these are all microporous, it is thought that low molecular weight silicone spreads, penetrates, and scatters into these exterior materials, and dust adheres to them, causing contamination. Ru. Additionally, the silicone sealant itself may become contaminated due to the generation of microorganisms.

This invention was developed in view of the above circumstances, and is designed to prevent dark contamination from occurring along the joints after filling. The purpose of the present invention is to provide a silicone knolling material for use.

For this purpose, the present invention is configured such that a base material mainly composed of silicone rubber is mixed with layered mineral powder and a hardening agent, thereby fixing the low molecular weight silicone within the sealant.

Layered mineral powders include fine-grained sericite (sericite),
Mica or the like can be used.

Sericite has the same mineral properties as muscovite and is naturally produced as fine crystals. Some of these occur as sericite schist, which is a dynamic metamorphosed rock of sedimentary rocks, and others are produced by hydrothermal metamorphism of igneous rocks. The former is not suitable due to its lack of elasticity and poor interfacial properties.

The latter is academically (X)0-1 (Y,)2-3 (Z)4 (0
) to (OH)2, where x=to, NaC,.

y=A4 p;8.　M；U　F 'l=8. ．． Al.

It is a three-layered mineral with the general formula, and is generally called sericite.

However, even though it is sericite mineral-wise in this sense, its performance differs greatly depending on the type of host rock, the composition of the hydrothermal solution, the conditions of formation (temperature, pressure), and the intended use.

As a result of comparative research, the host rock should be an acidic plutonic rock (e.g., granite, Hanabe diorite) with conditions of high temperature, high pressure, and good crystal growth. The type in which AZ+8 is replaced with F-Kichi2.M,'' in the central octahedron of It was not possible to produce a product with good effects based on the amount of grain.It is not easy to crush elastic flakes even with simple crushing, but even if you forcefully crush them, the finer they become, the smaller the aspect ratio (ratio of length to thickness). Therefore, the aspect ratio should be at least 100 or more with appropriate spacing, and particles with a particle size of 6μ or less should be
0, it is preferable to set it above. The selection of the host rock, the formation conditions, and the crystal structure are consistent with improving interfacial activity, and making the grains as fine as described above gives rise to colloidal characteristics, improves adsorption performance, and increases the aspect ratio. If the number of formations is increased, water 1. This is because it is highly effective in blocking oil, ions, etc. However, even though the grains are as fine as above, the aspect ratio is 1.
In order to achieve a thickness of 0.00 or more, industrial production is required to reduce the thickness from 0.05 μm to 0.01 μm, which is the most difficult task, and the success in achieving this after many years of research is the basis of the present invention.

A liquid silicone sealant was used in the example.Blend (weight ratio) Silicone rubber base material 100 Sericite 20 Hardening agent 10 First, sericite 20 was gradually added to the silicone body 100 while using a kneader for a long time. When kneaded and dispersed evenly,
It has good workability and the viscosity remains the same. Add hardener at this time. Lay this flat on a thick sheet of penetrating, colored paper (
Paint, but do not add sericite (・Do the same thing and compare the two. (This is a commonly used method.

The hardening status is the same for both, but the one with sericite added is
There is no surface gloss and no release of low molecular weight silicone is observed. After curing, the adhesive was so good that it could not be peeled off from the paper. On the other hand, those without sericite have strong gloss, release of oily substances, and poor adhesion to paper after hardening, making it easy to peel off. And the penetration into the paper is so large that it is clearly recognized. The blending amount of sericite is 5.10, 15.20 per 100 of the silicone main body.
, 25, the effect became more pronounced as the amount added was increased, and the difference in effect between 15 and 20 was small, so 1
A value of 5 to 20 is considered suitable for practical use.

Example 2 According to the above literature, when the contact angle of water dropped on the surface of a stone is measured as a parameter and expressed in relation to the distance from the joint, the contact angle tends to decrease as this distance increases. is proportional to the contact angle and the amount of low molecular weight silicone. It has been reported that when this value is 20 degrees or less, hardly any dust adheres to the surface.

Using this method in combination with the visual judgment method, we will show the results after 10 years using stone (Hanabe diorite) with a sericite composition of 20 (same weight ratio as in the above example), as shown in the drawing. become.

As described above, this invention mixes the layered mineral powder and the curing agent into the silicone rubber base material, so that low molecular weight silicone is adsorbed and fixed by the adsorption properties of the fine particles of the layered mineral powder, and the sericite with a large aspect ratio is Due to the blocking effect of the many layers of oriented flakes, not only does the low molecular weight silicone not escape from the outside, but it also prevents moisture from entering from other sources. As a result, it is possible to effectively prevent low molecular weight silicone from propagating, permeating, or scattering from the joints to the exterior material, so that the exterior material is not contaminated. Also, since moisture does not penetrate into this sealant,
No microorganisms are generated, and discoloration caused by microorganisms can be effectively prevented.

Since sericite is a mineral with strong electrical insulation properties, it prevents dust adsorption due to electrostatic charge. Since sericite is chemically stable, it does not resist the action of hardeners, and its characteristic lubricity improves the workability of sealants (and its strong elasticity, which is unparalleled in other minerals, is It greatly contributes to the performance of sealants.

[Brief explanation of the drawing] The drawing is a graph showing one implementation result of this invention. Patent applicant: Hikawa Seigyo Co., Ltd. (1 other person)

Claims (1)

[Scope of Claims] (1) A silicone sealing material for construction and civil engineering, characterized in that a base material mainly composed of silicone rubber is mixed with layered mineral powder and a curing agent. (2) The silicone sealing material for construction and civil engineering according to claim 1, wherein the layered mineral powder is interosseous fine sericite. (Good) The silicone sealing material for construction and civil engineering according to claim 1, wherein the layered mineral powder is mica. (4) Weight ratio of base material and sericite is 100:15-2
0. The silicone sealing material for construction and civil engineering according to claim 2.