JPS6017357B2 - Cement adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cement adhesive composition suitable for bonding inorganic tiles, stones, secondary cement products, etc.

Generally, cement has good adhesion properties, but the commonly used cement mixtures consisting of cement-water system or cement-aggregate-water system are affected by the ground conditions at the time of construction.
Adhesive properties are significantly affected by the properties of the adhesive, and in particular, if the adhesive material has high water absorption, dehydration from the adhesive layer may cause poor setting of the cement mixture or a decrease in plasticity. It has the disadvantage that it is difficult to obtain a strong adhesive force.

In order to eliminate the disadvantages mentioned above, the cement mixture may contain alkylcelluloses, hydroxyalkylcelluloses such as methylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, hydroxybutylmethylcellulose, hydroxyethylethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, or Attempts have been made to add and blend water-soluble nonionic cellulose ethers such as hydroxyalkylalkylcellulose.

These nonionic cellulose ethers all have a degree of etherification (degree of substitution D.S.) from the viewpoint of imparting water solubility.
) is used as being in the range of 1.6 to 2.5. Such water-soluble nonionic cellulose ethers have a thickening effect of increasing viscosity when dissolved in water, and also impart excellent water retention and plasticity to cement mixtures.

However, when cement mixtures containing water-soluble nonionic cellulose ethers as described above are used to bond inorganic tiles, stones, or cement-based secondary products, they harden from the surface of the applied amount. , a phenomenon occurs in which only the surface portion appears to be formed by a film (skinning phenomenon), and this phenomenon is particularly noticeable in conditions of high temperature and low humidity, and progresses rapidly over time.

Once the adhesive layer undergoes the skinning phenomenon, it loses its plasticity and cannot obtain the desired mechanical strength after curing. The effect becomes more pronounced as the amount of nonionic cellulose ether added increases. This is not a problem if the open time when applying a cement mixture containing non-ionic cellulose ether and adhering it to the adherend is relatively short, but in general, open time during construction work is relatively short. In many cases, it is necessary to take a certain amount of time, and in such cases, the mixture hardens while standing, making it difficult to obtain the desired adhesive strength, and in extreme cases, it may be difficult to obtain the desired adhesive strength. The problem is that it cannot be done.

The present invention aims to provide a cement-based adhesive composition which solves the above-mentioned conventional problems, and which contains 10 parts by weight of 'i} cement and 1.0 parts by weight of [o' substitution degree]. The main ingredient is 0.02 to 2 parts by weight of hydroxyalkyl cellulose which is soluble in water or alkaline water.

The present inventors have discovered that cement-based adhesives exhibit extremely good adhesion to inorganic tiles, stones, cement-based secondary products, etc., and can allow sufficient open time during construction work without any inconvenience. As a result of intensive research on the agent composition, as mentioned above, we used hydroxyalkyl cellulose that has a degree of substitution within a specific range of 1.2 to 1.5 and is soluble in water or alkali. They found that this is extremely effective and have completed the present invention.

The composition of the present invention exhibits excellent adhesion to various substrates and has the remarkable effect of having a longer open time (time until skinning phenomenon occurs) compared to conventional cement mixtures. I have it too.

The cement adhesive according to the present invention will be explained in detail below.

First, as the cement which is the main component (i) in the present invention, various conventionally known cements can be used, and specific examples include boltland cement, alumina cement, and blast furnace cement. .

Next, ' used in the present invention.

Hydroxyalkyl cellulose as a component is used for the purpose of imparting water retention to the cement, which is the above component, increasing the plasticity of the composition containing it, and providing open time. The degree of substitution (degree of nalization) of the hydroxyalkyl group is 1.2.
It is required to be soluble in water or alkaline water at ~1.5%. This is because when this composition is blended with water, sand, etc. and used as a paste adhesive as described later, the degree of substitution increases from 1.2 to 4, and a thickening effect is obtained. This is because the open time cannot be made sufficiently long if the degree of forgery is greater than 1.5.

Examples of such [o} component include hydroxyethyl cellulose and hydroxypropyl cellulose.

These are swellable in water and soluble in alkali when the degree of substitution is close to 1.2, and soluble in both water and alkali when the degree of substitution is close to 1.5.
From the viewpoint of achieving the above-mentioned purpose, the amount of this {o} component to be used is 0.02 to 0.02 parts by weight per 100 parts by weight of the above-mentioned components.
The amount is 2 parts by weight, preferably 0.05 to 1 part by weight.

In order to actually apply the mixture of these 'i} and [〇' components as an adhesive, it is sufficient to mix and knead the mixture with an appropriate amount of water and appropriate sand, etc., and use it as a paste-like product. .

In this case, as long as the purpose of the present invention is not impaired, in addition to the above-mentioned sand, natural aggregates such as jiyari, artificial bone aggregates, pigments, fillers, etc.
Inorganic or organic fibrous substances, resin emulsions, powdered resins, etc. may be added and blended. Next, examples of the present invention will be given, and in the following description, only parts or parts by weight are shown.

Example 1 Ordinary bolt land cement 10 foundation, river sand (grain ratio 2.
3) Hydroxyethyl cellulose with a degree of etherification of 1.5 (2% water-soluble viscosity of 4000 centipoise) 0
．． 2 parts and 40 parts of water are uniformly kneaded using a mortar mixer, and this kneaded mixture is immediately applied on a concrete plate to a thickness of 7 bars, and then the open time is set to 0 minutes, 30 minutes or After 60 minutes, a small flat porcelain tile was pressed onto the coated surface.

This product was left indoors for 4 weeks, and the adhesive strength between the tile and concrete after being left was examined using a Hoken type tensile tester, and the results shown in Table 1 below were obtained. . For comparison, a similar test was conducted on a mixture having the same composition as above, except that hydroxyethyl cellulose with a degree of etherification of 2.3 was used, and the results are shown in Table 1 below. Also listed.

Table 1 (Adhesion strength K / hot water) Each value in the table shows the average value of 5 test specimens) Example 2 In Example 1, hydroxyl with a degree of etherification of 1.5 When hydroxyethylcellulose with an etherification degree of 1.4 was used instead of ethylcellulose, and tests were conducted using the same machine at open times of 0 minutes, 30 minutes, and 60 minutes, the adhesive strength was almost the same. there were.

Claims (1)

[Scope of Claims] 1. (a) 100 parts by weight of cement, and (b) 0.02 to 2 parts by weight of water- or alkali-soluble hydroxyalkylcellulose having a degree of substitution of 1.2 to 1.5. adhesive composition