JPS6229384B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an extrusion molding composition suitable for producing cementitious materials by extrusion molding. Conventionally, thin plate-like cement products formed from cement compositions have been molded by a papermaking method, but products that are generally thick or have complex shapes have been molded. The mold forming method involves a number of steps such as cleaning the mold, assembling it, pouring mortar, demolding, and curing, so it is unavoidable that the product cost is relatively high even though it uses inexpensive raw materials. In addition, demolding takes a long time, the mold cost accounts for a high proportion of the manufacturing cost, and it is extremely difficult to economically mold the mold into a variety of shapes and sizes. In order to overcome this drawback, many methods, compositions, and devices for manufacturing cement products by extrusion have been proposed. The extrusion molding method can mold products of various shapes and sizes simply by changing the die, and has high productivity, so it can eliminate the drawbacks of the mold molding method. However, the shape retention of the raw mortar product discharged from the extruder is low, and the accuracy of shape and dimensions tends to decrease due to the so-called "sag" phenomenon. Furthermore, when the amount of water is reduced to improve shape retention, the fluidity of the mortar decreases, making it impossible to extrude or increasing the discharge pressure, resulting in a significant decrease in productivity. Furthermore, when a fibrous material such as alkali-resistant glass fiber or other easily breakable fibrous material or lightweight aggregate is mixed, there are many problems such as being easily broken, having a low reinforcing effect, and not being able to achieve weight reduction. This invention was made in view of the above problems, and its purpose is to improve the fluidity of mortar and the shape retention of raw mortar products when extruding cement products using an extruder. This paper proposes a cement composition that makes it possible to manufacture cement products of various shapes and sizes at low cost in response to market demands. The gist of this invention is that a cement mixture with a reinforcing material or an additive has an average diameter of 3 mm.
20 to 50 parts of the following wood powder per 100 parts by weight of cement.
This is a cement composition for extrusion molding, characterized in that it is made by adding parts by weight. When a mortar of this composition is extruded using an extruder, the wood flour in the mortar is compressed in the extruder and the moisture in the wood flour is squeezed out without adding excessive water to the mortar. The water is supplied as water between mortar particles, giving sufficient fluidity to the mortar, allowing efficient discharge and molding of uniform raw mortar products. When the raw mortar product is released from the pressure of the extruder, the wood flour inside it expands again and absorbs water, taking in the interparticle water that was necessary for fluidity, reducing fluidity and allowing it to maintain its shape. . Therefore, this composition can be efficiently extruded into a homogeneous raw mortar product using an extruder, and this raw product has high shape retention, so it can be made into a cement product while maintaining high precision in shape and dimensions. can. Furthermore, by using an extruder, products of various shapes and sizes can be produced economically and with high productivity, making it possible to supply high value-added products at low cost in response to market demands. . In addition, since the cementitious material obtained by molding this composition contains wood powder, it has physical properties not found in conventional GRC, making it suitable for building materials such as building exterior walls, partition walls, ceilings, and columns. can do. If a fibrous material is mixed as a reinforcing material to improve the strength, or a lightweight aggregate such as perlite is used as an aggregate, for example, if the total weight of wood flour and perlite is 25% or more of the cement. It can be processed by cutting, sawing, nailing, etc., and it can be made into a wood-like product that is lightweight, has excellent heat insulation, and has a rich texture, and can have surface dew condensation comparable to that of wood. Incidentally, small fragments of compressively deformable water absorbing materials such as paper, pulp, fibers, or plastic foam also have effects similar to the wood flour of this invention, but wood flour requires a larger amount compared to these materials. can be uniformly dispersed and mixed into the mortar, which improves the shape retention of extruded products, the protection of materials that are easily destroyed in the extruder, such as lightweight aggregates and alkali-resistant glass fibers, and the properties obtained by molding. It is extremely effective in improving the processability of processed products. Additionally, wood flour has the advantage of being stably supplied in both quality and quantity and being inexpensive. The wood flour used in this invention may be of either softwood or broadleaf wood, and has an average diameter of 3 mm or less, preferably 2 mm or less. If the average diameter exceeds 3 mm, compressibility and water absorption will decrease, making it difficult to satisfy the characteristics of this invention in terms of mortar fluidity and shape retention of raw mortar products, which are the characteristics of this invention. As the wood flour that satisfies these conditions, sawdust generated in ordinary sawmills is suitable.
It is economical and advantageous in terms of supply and resource saving. The amount of wood flour added is 20 to 100 parts by weight of cement.
In the range of 50 parts by weight. If it is less than 20 parts by weight, the ability to take in interparticle water during extrusion molding will be insufficient, resulting in poor shape retention, and if it exceeds 50 parts by weight, the proportion of cement will decrease too much, resulting in insufficient bonding ability of cement. As the cement used in this invention, portland cement, alumina cement, mixed cement thereof, etc. can be used. The composition of the present invention may be used as necessary with reinforcing materials such as various aggregates and fibrous materials, resin emulsions such as rubber latex, water-soluble polymeric plasticizers such as methoxy cellulose, colorants, curing rate regulators, and waterproofing agents. Other additives such as these may be included within a range that does not adversely affect extrusion molding. Among these materials, fibrous materials, lightweight aggregates,
Blending a resin emulsion such as diatomaceous earth or rubber latex is effective from the viewpoint of moldability or product properties. Fibrous substances that are effective in improving product strength by blending into this composition include alkali-resistant glass fibers, asbestos, carbon fibers, steel fibers, organic fibers (natural fibers, synthetic fibers), pulp, synthetic pulp (e.g. Zerapack manufactured by Mitsui Zellapack Co., Ltd.), etc. Both are cut into short fibers, mixed with composition mortar, and extruded. Particularly effective and practical materials to be mixed with are alkali-resistant glass fiber and asbestos. Alkali-resistant glass fiber (hereinafter referred to as ARG)
For example, a single yarn having a diameter of 7 to 30 μm and a fiber length of 5 to 50 mm is used. If it is less than 5 mm, the adhesion to the mortar layer will be insufficient, and if it exceeds 50 mm, it will be difficult to mix with the mortar, causing tangles, etc., and the effect of the length will be saturated. If the single yarn diameter is 7 μm or less, it becomes susceptible to erosion by the alkaline components of cement, reducing the reinforcing effect and causing problems in long-term durability. On the other hand, if it exceeds 30μ, the adhesion area of the mortar decreases and the anchoring force is insufficient compared to the tensile strength, and furthermore, it lacks flexibility, increases breakage, and reduces the reinforcing effect. The mixing amount is in the range of 0.5 to 50 parts by weight, preferably 2 to 20 parts by weight per 100 parts by weight of cement. During extrusion molding of mortar containing ARG in this composition, moisture in the wood flour is squeezed out and supplied as moisture between mortar particles, giving the mortar sufficient fluidity.
External stresses such as compression and bending are alleviated, making it possible to suppress damage to the ARG. In the case of conventional extrusion molding, ARG is significantly destroyed, but in the case of this composition, the fiber length can be kept long and the strength of the product can be efficiently improved. Another characteristic of adding ARG or other fibrous materials to this composition is that by extrusion, the fibers are oriented in the direction of extrusion, and in the case of columns or plates, the fibers are oriented in the longitudinal direction. It is possible to efficiently improve bending strength. Generally, when a fibrous material is premixed with mortar and molded into a mold, the mixture becomes random and the strength in the longitudinal direction is insufficient. Asbestos has a reinforcing effect, improves product strength, and at the same time smoothes the product surface. Also, similar to wood flour, during extrusion molding, it deforms under compressive force and releases or absorbs water, which is effective in improving the fluidity and shape retention of mortar. It also has a protective effect on ARGs. The amount of asbestos and other fibrous substances contained in the above ARG
0.5 to 30 per 100 parts by weight of cement, as in the case of
The amount ranges from 2 to 20 parts by weight, particularly preferably from 2 to 20 parts by weight. Examples of lightweight aggregates include natural lightweight aggregates such as volcanic sand, antihydrite grains, pearlite (pearlite, obsidian),
Artificial lightweight aggregates such as shirasu balloons, expanded shale, expanded clay, and expanded synthetic resin particles are effective, and pearlite is particularly optimal in terms of product specific gravity, workability, stable supply, and cost. The average particle size of the lightweight aggregate is preferably 3 mm or less. If it exceeds 3 mm, the fluidity of the mortar will decrease and it will be more likely to break during the extrusion process, which is not preferable. The amount of lightweight aggregate mixed in is determined based on a comprehensive judgment from the viewpoints of the product's design specific gravity, workability (sawing ability, nailing ability, etc.), and performance (strength, heat insulation, etc.). 10 to 100 parts by weight, especially 20 to 100 parts by weight
50 parts by weight is preferred. When extrusion molding mortar containing lightweight aggregate mixed into this composition, fracture can be suppressed to a low level due to the pressure buffering effect and plasticizing effect of wood flour, similar to when ARG is mixed. Therefore, it is possible to reduce the weight of the product, improve workability, etc. Diatomaceous earth has high water retention properties during the molding process, and is effective in increasing the retention of raw products and smoothing the surface of the product. If resin latex is added, the moldable moisture content of the mortar can be reduced, the strength of the product will be improved, and the product will become a polymer cement, improving its physical properties. Furthermore, it is present around the fibrous material to protect the fibrous material and improve its adhesion to cement. The amount of diatomaceous earth mixed in is in the range of 5 to 50 parts by weight per 100 parts by weight of cement, and the amount of resin emulsion mixed in is in the range of 1 to 30 parts by weight in terms of solid content. The composition of the present invention is mixed and kneaded with water to form a mortar and extruded, and the water content is in the range of 20 to 100% by weight (based on the total composition). The present invention has the above-mentioned structure and is a cement composition for extrusion molding made of a cementitious material to which wood flour is added. When this composition is extruded using an extruder, the mortar has good fluidity and extrusion efficiency is high, and the molded raw product has good shape retention and can be molded with high accuracy in shape and size. Unlike conventional products, there is no "sagging" phenomenon that degrades the accuracy of shape and dimensions. Furthermore, if a fibrous substance is added and mixed into this composition, the strength will be improved, and in particular, fibers that are easily broken and destroyed, such as ARG or carbon fibers, can be suppressed with low destruction and the strength can be efficiently achieved. Furthermore, by using lightweight aggregate etc., it is possible to reduce the weight and improve workability. As a result, the following effects can be brought about. Cement products with high shape and dimensional accuracy can be manufactured with high productivity and low cost. Products can be economically produced in a variety of shapes and sizes. If a fibrous material is added, it can be oriented in the extrusion direction and reinforced efficiently. In particular, fibers that are easily broken such as ARG are not easily destroyed, and a high reinforcing effect can be achieved. Examples and comparative examples are shown in the table below. The raw materials and extrusion equipment used in each example are as follows. Cement: Ordinary Portland cement manufactured by Ube Cement Co., Ltd. Wood powder: Sawdust passed through a 2 mm pass, Fibrous substance: Alkali-resistant fiber: Cem manufactured by Pilkington Co., Ltd.
- Fil” chip strand fiber length 24mm, acrylic fiber: Asahi Kasei Co., Ltd. “Cashmilon”
5d, fiber length 30mm Asbestos: "6D-04" manufactured by Johns Manwill Co., Ltd. Lightweight aggregate: Perlite: "Fuyolite No. 1" manufactured by Fuyolite Co., Ltd. Plasticizer: "Metrose" manufactured by MC Shin-Etsu Chemical Co., Ltd. Extruder: Miyazaki Iron Works "FM-D type" extrusion molded sample: Hollow prism side a (100mm□) -
Diameter r (70mmφ) (as shown in the drawing)

【table】

【table】 [Brief explanation of the drawing]

The drawings are cross-sectional views showing extrusion molded samples of Examples and Comparative Examples and their distortions.

Claims (1)

[Claims] 1. 20 to 50 parts by weight of wood powder with an average diameter of 3 mm or less is added to 100 parts by weight of cement to a mixture of cement and reinforcing materials or additives. Characteristic cement composition for extrusion molding. 2 The mixture uses fibrous material as a reinforcing material and cement.
The cement composition for extrusion molding according to claim 1, wherein the cement composition is blended in an amount of 0.5 to 30 parts by weight per 100 parts by weight.