CN100396640C - Composite wall material of magnesite and paper fiber and its production method - Google Patents

Abstract

A composite wall material of magnesite and paper fiber, which is composed of the following raw materials and their weight ratios: 90 parts of magnesite, 30-100 parts of water, 5-20 parts of magnesium chloride as an activator, 1-5 1 part fiber, 1-10 parts reinforcing agent. The production method of the composite wall material is carried out according to the following steps: pretreatment of raw materials; weighing and mixing of raw materials to form slurry; molding into a mold; heating and curing; demoulding and drying; sawing test. The production of this wall material has the advantages of waste utilization, less wood (paper) fiber consumption, low energy consumption, low equipment investment, and short production cycle. Thermal and excellent physical and mechanical properties, etc., can be widely used in the construction industry as decorative materials.

Description

Composite wall material of magnesite and paper fiber and its production method

technical field

The invention relates to a wall material compositely formed by using magnesite and paper fiber as main materials and a production method thereof.

Background technique

A number of patents have been published on the technology of making lightweight boards from Portland cement or magnesium cement combined with wood wool or shavings. The board is light and porous, mainly composed of wood wool and wood shavings. Depending on the pores, the amount of wood wool or shavings is almost 1/3-1/2 of that of magnesite, which is a pity in today's scarcity of wood raw materials. CN1861352A discloses Zhonglin Nanxing (Huzhou) Plywood Co., Ltd.'s patented technology of "manufacturing light-weight magnesite wood wool boards by autoclaving", using MgCl ₂ solution, magnesite, and wood wool to mix, paving and pre-pressing, Compressed and solidified in a closed press with a steam generator. This technology needs a press with a large investment, and the ratio of wood wool and magnesite in the board produced is 1:1.5-2.0, which consumes a lot of wood fiber, and the curing and tempering period is long, which affects the production cycle.

Contents of the invention

In order to reduce the equipment investment for producing composite wall materials and reduce the consumption of wood (paper) fibers, the present invention designs a composite wall material of magnesite and paper fiber and its production method, which greatly reduces equipment investment costs and Reduce the amount of wood (paper) fiber, shorten the production cycle, and the products made are porous, waterproof, fireproof, mildewproof, mothproof, and have sound and heat insulation properties.

The technical solution of the present invention to solve the above-mentioned technical problems is: it is formed by the following raw materials and their weight ratios: 90 parts of magnesite, 30-100 parts of water, 5-20 parts of magnesium chloride as an activator, 1-5 parts of paper At least one of fiber, 1-10 parts of silane coupling agent used as reinforcing agent, polyacrylate emulsion and polyvinyl acetate emulsion.

The optimum weight ratio of each raw material is: 90 parts of magnesite, 40-60 parts of water, 10 parts of magnesium chloride, 2 parts of paper fiber, and 5-6 parts of reinforcing agent.

Said reinforcing agent is at least one of silane coupling agent, polyacrylate emulsion and polyvinyl acetate emulsion, and the best solution is the mixed liquid of silane coupling agent and polyvinyl acetate emulsion.

The production method of this magnesite and paper fiber composite wall material is to carry out according to the following steps:

(1) Pretreatment of raw materials: Drying, pulverizing, screening of magnesite, cutting waste paper into thin strips, pulverizing, homogenizing, and preparing MgCl _aqueous solution for subsequent use;

(2) Weighing and mixing the raw materials into a slurry;

(3) into the mold;

(4) heating and curing;

(5) demoulding and drying;

(6) sawing and testing.

The beneficial effects of the present invention are: less wood (waste paper) fiber is consumed, and it is a kind of waste utilization, which greatly saves wood raw materials that are lacking in daily sense; no need to buy a press, and the investment in equipment is saved; the maintenance period is saved, The production cycle is shortened.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples: First, each production step is introduced in detail.

(1) Pretreatment of raw materials. Select magnesite with Mg0 content of 75-85%, dry it, crush it, screen it, and use 50 mesh to 300 mesh as raw material; first cut the waste paper into 5×30mm thin strips, and then make it in a crushing and homogenizing machine Pulp; make a MgCl _aqueous solution with a content of about 30% for subsequent use.

(2) Weighing and mixing the raw materials into a slurry. Weigh according to the designed weight ratio of each raw material, and then mix thoroughly to form a slurry.

(3) into the mold forming. In order to save cost, the wooden mold is prefabricated according to the design specifications, poured into the mold for molding, and the mold is vibrated when entering the mold to make the filling full.

(4) Heating and curing. Curing at 80°-160°C for 0.5-2.0h, the curing time is determined by temperature, material shape and thickness.

(5) demoulding and drying. Cool to below 40°C, film mold without burning your hands, if it is not dry, you can reheat and dry it or dry it naturally.

(6) sawing and testing. Sawing according to the user's size requirements or only for trimming, and inspecting and testing according to the product standard requirements and related mechanical properties.

Example:

Choose 80% MgO content, 90 kg of magnesite with a particle size of 150 mesh, 40 kg of water, 10 kg of _an aqueous solution with a MgCl content of 30%, 2 kg of paper fibers, 5 kg of polyvinyl acetate emulsion, and 0.08 kg (80 g) of silane Mix the coupling agent into the cement mixer and mix well, then pour it into the mold placed on the vibrator one by one, make it full, and then move it to the drying room. Curing at 160°C for 2 hours, or at 160°C for 0.5h, after cooling down to below 40°C and demoulding, the drying requirement has basically been met, and it can be sawed or trimmed immediately for testing. If it is made into a brick-shaped material, it can be cured at 160°C for 0.5h, and then stacked to dry naturally. If the requirements for surface flatness are low, it can be used for building walls without sawing or trimming.

The following is a list of laboratory comparative tests on the impact of the addition of some raw materials on the performance of composite wall materials.

Effect of water addition on performance (Table 1)

serial number Amount of water added (ml) Density (g/cm³) Internal bonding strength (Mpa) Strength to weight ratio 1 40 1.294 0.588 0.454 2 60 1.278 0.412 0.322 3 80 1.340 0.393 0.293 4 100 1.263 0.396 0.313

Table 1 shows that the amount of water added has a great influence on the internal bonding strength and the strength-to-weight ratio. The amount of water added is inversely proportional to the internal bonding strength, and 40-60ml is preferred.

When the curing temperature is 180°C, the paper fibers are easy to carbonize, the plasticity decreases, and cracking occurs. Therefore, the maximum curing temperature is limited to 160°C, and it is more appropriate to control it at 80-160°C.

The effect of the amount of pulp added on the performance (Table 2)

serial number Paper fiber (g) Density (g/cm³) Internal bonding strength (Mpa) Strength to weight ratio 1 0 1.304 0.287 0.220 2 2 1.294 0.588 0.454 3 3 1.201 0.396 0.330 4 4 1.042 0.227 0.218 5 5 0.897 0.126 0.140

Table 2 shows the effect of pulp addition on performance when the water addition is 40ml and the curing temperature is 160°C. It shows that the addition of paper fiber has a great impact on the three properties, and the addition of 2-3g is preferred.

The applicant also conducted a comparative test on which reinforcing agent to add, whether a single reinforcing agent or a mixture reinforcing agent, and the best effect was to use 5 parts of polyvinyl acetate emulsion and less than 1 part of silane coupling agent as the reinforcing agent. Not detailed due to space limitations. The "strength-to-weight ratio" listed in the table refers to the ratio of the same weight of material to strength, that is, internal bonding strength/weight.

Among the raw materials of the present invention, magnesite is calcined with magnesite, which is a powdery air-hardening cementing material, and its main component is magnesium oxide, which has fast setting and hardening, high strength, weak alkalinity, easy combination with organic matter, and fire prevention , waterproof and other properties, in the present invention, with the magnesite of fixed 90 parts by weight as a benchmark, the proportioning amount of other raw materials is calculated, and of course the reverse calculation of the proportioning amount is also feasible.

Whether the pulp is added or not, more or less, has a significant impact on the performance of the composite wall material. It plays a role in pulling and improving toughness. It does not work if no or more pulp is added, and the converted paper fiber is 2 Parts by weight are best. The paper fibers are interspersed, overlapped and connected in the magnesite to form a three-dimensional network structure, which improves the performance of absorbing and dispersing impact energy, and makes the composite wall material have good impact resistance and toughness.

Add polyvinyl acetate emulsion, a high-molecular polymer, during the curing process, it can generate a high polymer around the complex and cover the Mg(OH) ₂ crystals, forming a good waterproof protective layer, and at the same time, it is also between the crystals. Self-crosslinking and blocking capillary channels in the gaps, reducing the contact between chloride ions and water molecules, and improving the stability of the complex structure in water. The silane coupling agent contains a long bond segment, which can form a flexible stress-relaxed interface layer, improve the impact strength and toughness of the wall material, and the coupling agent can change the bonding of the material into a covalent bond, increasing the The affinity between magnesite and paper fiber acts as a molecular bridge, which not only increases the strength, but also increases the amount of magnesite to reduce paper fiber consumption and production costs.

After homogenization of magnesite, pulp, water, MgCl ₂ , polyvinyl acetate emulsion, and silane coupling agent, the bonds are combined to form a grid structure, and the water molecules in the structure are heated and solidified, dehydrated and evaporated to form micropores Composite wall material.

Claims (2)

1. magnesia and paper fibre composite wall material is characterized in that being formed by following raw materials according and weight part proportioning thereof: 90 parts of magnesias, 30-100 part water, 5-20 part are done in the silane coupling agent, polyacrylate dispersion, polyvinyl acetate emulsion of toughener at least a as magnesium chloride, 1-5 part paper fiber, 1-10 part of activator.

2. the production method of magnesia as claimed in claim 1 and paper fibre composite wall material is characterized in that following these steps to carrying out:

(1) pre-treatment of raw material: with magnesia drying, pulverizing, screening, waste paper is cut into slice, pulverizing, homogenate, system MgCl ₂The aqueous solution is standby;

(2) weighing of raw material and mix well pulping;

(3) go into mold forming;

(4) heating cure;

(5) demoulding drying;

(6) saw cuts and test.