JPH01224253A - Production of calcium silicate-polymer composite board - Google Patents

Abstract

PURPOSE:To obtain the subject composite board having light-weight and high strength, in high efficiency, by dripping an anionic polymer flocculent to an aqueous slurry containing hydrated calcium silicate, a styrene-butadiene latex, cellulose fiber and a cationic latex fixing agent and forming the mixture in the form of a board. CONSTITUTION:A slurry having a solid content of 0.5-4wt.% is produced by compounding 100pts.wt. of calcium silicate hydrate having a sedimentation volume of >=10ml/g with 3-15pts.wt. of styrene-butadiene latex, 1-5wt.% (based on the solid content of the slurry) of cellulose fiber having a freeness of <=350ml, 1-20wt.% (based on the styrene-butadiene latex) of a cationic latex fixing agent and water. The slurry is poured into a paper-making vat while dripping 20-10,000ppm (based on the solid content of the slurry) of an anionic polymer flocculent and formed in the form of a board to obtain the objective calcium silicate-polymer composite board.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing a calcium silicate/polymer composite plate by a papermaking method, and more specifically, it relates to a method for producing a calcium silicate/polymer composite plate by a papermaking method, and more specifically, it relates to a method for producing a calcium silicate/polymer composite plate by fixing a polymer on a calcium silicate hydrate to form a circular wire, fourdrinier or The present invention relates to a method for producing a lightweight calcium silicate/polymer composite plate having a thickness of 15 mm or less using a flow-on method.

[Prior Art/Problems] Conventionally, a method for manufacturing calcium silicate plates having a thickness of 151 mm or less has generally been based on a papermaking method, which is also specified in JIS^5418. The product with the lightest bulk specific gravity specified in this regulation is one with a bulk specific gravity of 0.8 (+0.1.-0.2), and within this bulk specific gravity range, it has poor cutting properties compared to wood, and it is difficult to process. The drawback was that it was difficult to do. Also, if the bulk specific gravity is lower than the range shown in this regulation, the strength will be weakened,
Practicality as a plate-like product with a thickness of 151 mm or less could not be obtained.

Unexamined Japanese Patent Publication No. 1983-1982 as a proposal to make it lighter and stronger
No. 138351, it is possible to obtain products that are lighter and heavier and have higher strength than the products specified in JIS^5418, but they still have the drawbacks of poor toughness and poor cutting and workability compared to wood.

To improve this toughness, a calcium silicate polymer composite was devised. The manufacturing method of this calcium silicate polymer composite is disclosed in Japanese Patent Publication No. 52-39702 and Japanese Patent Application Laid-open No. 52-39702.
These techniques are disclosed in Japanese Patent Publication No. 2-15516, Japanese Patent Publication No. 62-32148, etc., but the molding methods of these technologies are all based on mold press, and in order to facilitate dewatering, a wire mesh or mesh is placed on the press surface. Since it is spread with cloth, it is difficult to obtain a smooth surface, and the drainage during dehydration tends to cause defects inside, making it difficult to produce molded products with a thickness of about 15 i* or less.

Therefore, in order to obtain a plate-shaped molded product with a thickness of 15 m or less, the current method is to once form a molded product with a thickness of about 15 mm using WJI, and then manufacture it to the desired thickness by polishing or the like. For this reason, the productivity of manufacturing thin products is poor, the cost is high, and even if a polishing process is used, it is difficult to manufacture products with a thickness of 8 cm or less.

Furthermore, the basic molding method of JP-A-62-52159 is extrusion molding, which essentially differs in principle from the papermaking method.

Therefore, the object of the present invention is to produce a calcium silicate plate using the conventional papermaking method or a calcium silicate plate using the mold press method.
The purpose of the present invention is to provide a method for efficiently producing lightweight and high-strength thin calcium silicate plates by improving the production and performance disadvantages of polymer composite plates, that is, problems related to productivity, strength, and workability.

[Means for Solving the Problems] That is, the present invention uses calcium silicate hydrated Th1OO parts by weight with a sedimentation volume of 10 mf/9 or more, 3 to 15 parts by weight of styrene-butadiene latex, and cellulose with a sedimentation volume of 3'10 ml or less. A slurry with a solid content of 1 to 5% by weight of the fibers, a cationic latex fixing agent of 1 to 20% by weight of the styrene-butadiene latex, and water with a solid content concentration of 0.5 to 4% by weight is prepared. A calcium silicate polymer characterized in that when the slurry is poured into a papermaking vat, an anionic polymer flocculant is added dropwise in an amount ranging from 20 to 10,000 pp- of the solid content of the slurry. Pertains to a method of manufacturing a composite plate.

[Function] In the method of the present invention, calcium silicate hydrate 1 is added to an aqueous slurry containing calcium silicate hydrate and cellulose fiber.
00 parts by weight of styrene-butadiene latex
In order to efficiently fix the styrene-butadiene latex by adding within the range of ~15 parts by weight, 0.5 to 3 parts by weight of a cationic latex fixing agent is added to the latex, and after fixing, the slurry is made into paper. It is something.

The calcium silicate hydrate used in the present invention has a CaO/SiO2 molar ratio of silicate raw material and lime raw material of about 0.8 to 1.2, and in order to further reduce the weight (high bulk), the silicate It is obtained by hydrothermal synthesis using amorphous silicic acid for 40 to 80% of the raw material and setting the water vapor pressure to 5 kg/c112 or more. Calcium silicate hydrate synthesized under the above conditions has a sedimentation volume of 10 d/g or more.

The sedimentation volume of the calcium silicate hydrate described in this specification was measured as follows: First, the solid content concentration of the calcium silicate hydrate obtained by the hydrothermal synthesis method was measured,
Weighed the solid content equivalent amount 202 and found 10100O! Transfer to a measuring cylinder and make up to 1000 ml with distilled water to the marked line. Mix by inverting the measuring cylinder up and down 10 times to prevent the slurry from leaking, and then let stand. After 24 hours, the volume occupied by the solids is read and converted to the sedimentation volume per contract.

In the method of the present invention, P ice charcoal (C3F)3 is added to the aqueous slurry of calcium silicate in advance to make it suitable for papermaking.
An aqueous slurry is prepared by adding cellulose fibers beaten to below 50s+1.

NBKP, LBKP, etc. can be used as the cellulose fiber. The appropriate amount of cellulose fiber added is about 1 to 5% by weight of the solid content of the aqueous slurry.

If the amount of cellulose fiber added exceeds 5% by weight, the performance of the calcium silicate/polymer composite plate, which is required to be non-flammable, will deteriorate, making it undesirable.If it is less than 1% by weight, fine particles may be lost during paper making. This is undesirable because it increases the number of ingredients in the product, resulting in a component composition that is far removed from the prescribed ingredients, and properties such as strength of the product deteriorate.

In the present invention, the use of cellulose fiber improves paper formability and also contributes to improving the strength of the obtained molded plate, but if necessary, it may also be used in combination with glass fiber, vinylon fiber, acrylic fiber, etc. It is also possible to improve the strength and impact resistance of the obtained molded plate.

In the method of the present invention, since styrene-butadiene latex is added to an aqueous slurry containing calcium silicate hydrate and cellulose fiber, the P aqueous property of the slurry is extremely reduced. As a result, the papermaking properties are further deteriorated. During papermaking, it is essential to add a cationic fixing agent in order to improve the P aqueous property and the fixing rate of the added latex.

The amount of these fixing agents added is 0.5 to 20% by weight based on the styrene-butadiene latex added to the slurry, from the viewpoint of efficient paper making and the performance of the styrene-butadiene latex on the molded plate. is also necessary.

The solid content concentration of the aqueous slurry containing the calcium silicate hydrate, cellulose fiber, styrene-butadiene latex, and cationic latex fixative is 0.5 to 4.
It is preferable to adjust the weight to about 1% and use it for papermaking.

In order to further improve the papermaking properties of the slurry obtained by adding a cationic latex fixing agent as described above, it seems necessary to form stable flocs. For this purpose, it is desirable to first add a cationic latex fixing agent and then add an anionic polymer flocculant.

The amount of the anionic polymer flocculant added is within the range of 20 to 10,000 ppm based on the solid content in the slurry, and a slurry having stable flocs can be obtained with the amount added within this range. Specific examples of anionic polymer flocculants include polyacrylamide-based ones.

The slurry to which the anionic polymer flocculant has been added is made into paper using a circular wire, Fourdrinier, or flow-on type paper making machine, and the resulting sheet material is dried or, if necessary, pressurized by pressing. It is also possible to increase the bulk specific gravity by molding.

[Example] The method for manufacturing a calcium silicate/polymer composite plate according to the present invention will be further explained by giving examples below.

Preparation of silica and calcium Under the raw material composition and hydrothermal synthesis conditions listed in Table 1 below, the sedimentation volume is 6 ml/g, 8 d/g, 10 ml/g, and 13 m.
A calcium silicate hydrate [xonotlite (hereinafter abbreviated as Xo)] of l/g and 16d,'g was obtained.

Large IL top 2 sedimentation volume 10ml/9.1 produced as above
100 parts by weight of Xo solids at 3 mN/g and 16 ml/g, 8 parts by weight of carboxy-modified styrene-butadiene copolymer latex, 5 parts by weight of cellulose fibers with P bark of 300 wbl (4.39% by weight based on the solid content of the slurry), and fixed. A slurry having a slurry concentration of 2.2% by weight was prepared by adding and mixing 0.8 parts by weight of cation type polydialkylaminoalkyl (meth)acrylate (10% by weight based on the latex) and 5000 parts by weight of water as an agent.

Next, 134 parts by weight of O and C (300 ppm based on the solid content in the slurry) of anionic polyacrylate and lylamide as a flocculant were added to the above-mentioned slurry, and the resulting green board was made into a paper sheet using a circular paper making method. A 6-ring thick calcium silicate polymer composite board was produced by drying at 110"C. The properties of the resulting composite board are listed in Table 2 below.

Calcium silicate-polymer composite plates were manufactured using the same formulation as in Example 1, except that the amount of water added was varied to obtain slurries of various concentrations.

The amount of added water and the properties of the resulting composite board are listed in Table 3 below.

9-11 ・1 Sedimentation volume 8 me/g, 100 parts by weight of Xo solids of 1/9.13 theory 1/g and 16 d/g, 8 parts by weight of carboxy-modified styrene-butadiene copolymer latex, 300 af of P ice charcoal 5 parts by weight of cellulose fiber (4.36% by weight based on the solid content of the slurry), 0.0 parts by weight of cationic polydialkylaminoalkyl (meth)acrylate as a fixing agent.
8 parts by weight (10% by weight based on latex), 1 part by weight of glass fiber and 5,600 parts by weight of water were added and mixed to prepare a slurry having a slurry concentration of 2.0% by weight.

Next, 0.034 parts by weight of anionic polyacrylamide (300 ppm based on the solid content in the slurry) was added to the above slurry as a coagulant, and the resulting green board was made into paper using a round net paper making method. A calcium silicate/polymer composite plate having a thickness of 6 mm was produced by drying at .degree. Characteristics of the obtained composite plate: 11λ 1/g, sedimentation volume 10 1/9, 13 1/g and 16 1/g
4.5 parts by weight of cellulose fiber (4.26% by weight based on the slurry solid content), 1 part by weight of glass fiber, and 5600 parts by weight of water were added and mixed to 100 parts by weight of XO solid to make a slurry concentration of 2.0% by weight. A slurry was prepared.

Next, 0.034 parts by weight of anionic polyacrylamide (300 ppm based on the solid content in the slurry) was added to the above slurry as a coagulant, and the resulting green board was made into paper using a round net paper making method. A molded plate with a thickness of 6 mm was produced by drying at C.

The properties of the molded plate obtained are listed in Table 5 below.

±Shuku" LΣ Add and mix 100 parts by weight of slaked lime, 44 parts by weight of diatomaceous earth, 51 parts by weight of silica sand, 15 parts by weight of perlite, 11 parts by weight of cellulose fiber and 1 part by weight of 5,300 parts of water to create a settling volume of 6 d/
A mixture slurry of g was prepared. The resulting mixture slurry was made into a paper using a round net paper making method, and then autoclaved using a conventional method to produce a calcium silicate plate having a thickness of 6+am. The bending strength of this calcium silicate plate is 100
It showed a high value of ky/cI of 112 and width of 70 kg/am2, but its bulk specific gravity also showed a high value of 0.82.

Add and mix 100 parts by weight of slaked lime, 1 part by weight of diatom ±44 parts, 51 parts by weight of silica sand, 60 parts by weight of perlite, 13 parts by weight of cellulose fiber and 8500 parts by weight of water to obtain a sedimentation volume of 8 ml.
/H mixture slurry was prepared. Using the obtained mixture slurry, the same operation as in Comparative Example 6 was performed to obtain a thickness of 6.
A calcium silicate plate of - was manufactured. The bending strength of this calcium silicate plate is 43 ky/cm' vertically and 28 ky/cm' horizontally.
ky/cm2, and the bulk specific gravity was 0.61.

12-18. γ Calcium silicate/polymer composite plates were manufactured using the same formulation as in Example 1, except that the amount of added caloric water was varied to obtain slurries of various concentrations.

The amount of added water and the properties of the resulting composite board are listed in Table 6 below.

Methods 19-20 - 8-10 Slurries were prepared with the same composition as in Example 9 with a concentration of 2.3% by weight and 2.1% by weight, and silicic acid was added using the same method as in Example 9 using the circular paper making method. A calcium-polymer composite board was manufactured.

In addition, as a comparison product, a molded plate was manufactured by a mold press method using a slurry having the formulation described below.

The slurry used to produce the comparative product had a sedimentation volume of 10
-1/g of Xo solids, 8 parts by weight of carboxy-modified styrene-butadiene copolymer latex, 1.5 parts by weight of cellulose fiber (1.29 parts by weight based on the solid content of the slurry)
% by weight), 0.8 parts by weight of cationic polydialkylaminoalkyl (meth)acrylate as a fixing agent (10% by weight based on the latex), and 6 parts by weight of glass fiber. Note that the slurry concentration is listed in Table 7.

! A calcium silicate/polymer composite board having a thickness of 6 rings was produced by pressing the raw boards obtained by the round net papermaking method in Examples 9 and 10 to adjust the bulk specific gravity. The properties of the obtained calcium silicate/polymer composite board are listed in Table 8 below.

[Effects of the Invention] The present invention uses calcium silicate hydrate having a specific sedimentation volume obtained in advance by hydrothermal synthesis, and further specifies the slurry concentration during papermaking, thereby producing a calcium silicate board by a papermaking method. This method is an improvement on the conventional manufacturing method, and enables the efficient production of thin calcium silicate/polymer composite plates that are lightweight, have high strength, are tough, and have improved machinability.

Claims (1)

[Claims] 1. 100 parts by weight of calcium silicate hydrate having a sedimentation volume of 10 ml/g or more, styrene-butadiene latex 3-
15 parts by weight, cellulose fibers with a freeness of 350 ml or less are mixed into a slurry with a solid content of 1 to 5% by weight, a cationic latex fixing agent is mixed with 1 to 20% by weight of the styrene-butadiene latex, and water to make a solid content. Concentration 0.5-4
% by weight, and when the slurry is injected into a papermaking vat, an anionic polymer flocculant is further added dropwise in an amount ranging from 20 to 10,000 ppm of the solid content of the slurry. Method for manufacturing calcium-polymer composite board. 2. The method for producing a calcium silicate/polymer composite board according to claim 1, wherein the slurry contains one or more types of fibers selected from the group consisting of inorganic fibers and organic fibers.