JPS602305A - Formwork-panel made of metal for concrete having excellent mold release characteristic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal formwork/panel for concrete that has good mold releasability.

More specifically, (A) 10 to 11 parts of a modified polyolefin resin to which 5% by weight or less of an unsaturated carboxylic acid or a derivative thereof has been added and (B) an unmodified polyolefin resin are added to at least the contact surface of the metal formwork/panel for concrete with the concrete. It is made by laminating a composition consisting of 90 to 20 parts by weight of a polyolefin resin and 0.01 to 460 parts by weight of an unsaturated carboxylic acid or its derivative, and has good peelability from concrete and produces smooth and beautiful concrete. It relates to formwork and panels that can provide surfaces.

Conventionally, concrete formwork and panels are broadly divided into wooden formwork and panels made of plywood, particle board, etc., and metal formwork and panels made of ordinary steel, copper-containing steel, galvanized steel, aluminum, etc. be done.

Wooden forms and panels such as the veneer plywood mentioned above are usually used by applying a mold release agent or paint such as urethane, acrylic, or epoxy to the plywood surface, taking advantage of their low cost. The dimensional stability of concrete molded products is poor;
It has the disadvantage of poor durability.

On the other hand, metal formwork and panels are more expensive than wooden ones, but they have the advantage of superior dimensional stability and durability, and especially when used for formwork, they can be reused many times. Demonstrates the advantage of rapid growth.

However, the metal formwork and panels mentioned above are also wooden formwork and
Similar to panels, it has problems such as poor mold releasability and poor finished surface of concrete molded products.

One method for solving the above problems is to apply a mold release agent. However, problems arise, such as the control of the mold release agent, the complexity of application, and the impact on the quality of the surface of the concrete molded product.

Another method is to form a synthetic resin coating on the surface of a metal formwork or panel using an adhesive or the like. However, since it requires the use of an adhesive, it not only involves many complicated steps, but also has economical problems because it has a two-layer structure.

In addition, JP-A-Sho! uses an adhesive polyolefin resin instead of the above adhesive. 14-162823 or Japanese Utility Model Application Laid-Open No. 57-109147. However, the former has the same drawbacks as the above-mentioned adhesive, and the latter has difficulty in releasability.

In view of the above-mentioned problems, the inventors of the present invention have conducted extensive studies with the aim of providing metal forms and panels for concrete that have excellent characteristics such as releasability, smoothness, durability, and robustness. This led to the invention.

In other words, the present invention provides molds 10 to 80 of a modified polyolefin resin to which (A) unsaturated carboxylic acid or a derivative thereof is added in an amount of 5% by weight or less, at least on the contact surface with concrete of a metal formwork/panel for concrete. and (E3) 90 to 20 parts by weight of unmodified polyolefin resin,
Unsaturated carboxylic acid or its derivative 0.01-4% by weight
The present invention provides a metal formwork/panel for concrete, which is formed by laminating a composition containing the following.

What is the polyolefin <;I fat used in the present invention (L(
, medium- and high-density polyethylene, polypropylene, homopolymers such as polybutene-1, poly-4-methyl-pentene-1, and other α-polymers whose main components are ethylene and propylene.
Copolymers with A-refins or polar supermers, e.g.
Ethylene-propylene copolymer, ■Dylene-butene
1 copolymer, 1 ethylene-hexene-1 copolymer, ethylene-4-methyl-pentene-1 copolymer, ethylene-octene-1 copolymer or propylene-ethylene copolymer, propylene-butene-1 copolymer or 1 tyrene-I! Examples include l1flQ vinyl copolymer, ethylene-acrylic acid monomer, and/or mixtures thereof.

On the other hand, metal formwork/panel C is made of steel such as steel, aluminum-containing steel, galvanized steel, aluminum, copper, zinc, etc.
Examples include alloys such as brass.

In addition, the modified ('I) polyolefin resin of the present invention is one obtained by reacting the polyolenoin 481 resin with an unsaturated carboxylic acid or its derivative in an amount of 5% by weight or less, and the unsaturated carboxylic acid or its derivative contains a carboxylic acid group. , acid anhydride groups, ester groups, carboxylic acid amide groups, carboxylic acid metal salts, etc., and specifically monobasic acids such as acrylic acid, acrylic esters, methacrylic acid, and methacrylic esters. and maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, maleic acid monomethyl ester, maleic acid diethyl ester,
Examples include 2ml acids such as monomedyl ester fumarate, and maleic anhydride is particularly preferred. The amount of the unsaturated carboxylic acid or its derivative added is selected to be 5.0% by weight or less, preferably from 0.1 to 4.0% by weight. If the amount of the unsaturated carboxylic acid or its derivative exceeds 5.0 wt.

A known method may be used to obtain a modified polyolefin resin by adding an unsaturated carboxylic acid to the above-mentioned polyolefin resin. For example, an unsaturated carboxylic acid such as maleic anhydride is added to a polyolefin resin melted in a Banbury mixer or an extruder, etc. It can be obtained by adding a carboxylic acid or its derivative and an organic peroxide and carrying out a mixed reaction. Further, any method may be selected, such as a method of reacting the above composition in a solvent such as xylene.

In the present invention, it is important to mix 10 to 80 parts by weight of the above-mentioned modified polyolefin resin, preferably 15 to 60 parts by weight, and 90 to 20 parts by weight, preferably 85 to 40 parts by weight of the unmodified polyolefin resin. By mixing them in the same manner, the adhesive strength with metal and the mold releasability with concrete can be satisfied at the same time, and the conventional complicated process can be simplified and the product can be made economically inexpensive. If the content of the modified polyolefin resin in the composition is less than 15 parts by weight, the adhesive strength will be low, and if the content of the modified polyolefin resin exceeds 80 parts by weight, the mold releasability from concrete will be poor, and the surface condition of the concrete will deteriorate. Both are undesirable.

Further, the content of the unsaturated carboxylic acid or its derivative in the above composition is 0.01 to 4. It is important that the amount of OM is %. When the content of unsaturated carboxylic acid or its derivative is less than 0.01% by weight, the adhesive strength with metal is weak. Further, if the content exceeds 4.0% by weight, no improvement in adhesive strength can be expected, which not only results in high economic costs, but also may cause gelation in some cases.

The method of mixing the above composition is not particularly limited, and any method such as melt blending or triblending using a Banbury mixer, kneader 1 extruder, etc. can be selected.

In addition, melt indexes of the above composition (hereinafter simply M
l) is 0.5 to 50 (1/10 min, preferably 1
Selected in the range of ~20'J710 minutes. If the above MI is less than 5 g/'io min, the surface condition after coating may be impaired, and if the Ml exceeds 50 g/10 min, the physical properties of the coating layer will be significantly deteriorated, resulting in poor durability and
Difficulties such as sagging of the resin may occur during robustness or coating processing.

Methods for laminating the above composition onto a metal formwork or panel include a method in which the composition is formed into a film, laminated onto a formwork or panel that has been previously heated or chemically treated if necessary, and fused and bonded; A common laminating method may be used, such as forming the powder into a powder and laminating it by electrostatic coating, fluidized dipping, powder spraying, etc., and the thickness of the laminated film is 50 μm.
It is preferable to laminate the layers in a range of I11 to 5 mm, preferably 100 μm to 3 mm. If the thickness is less than 50 μm, durability and robustness will be compromised, but the number of uses will not be affected. On the other hand, if the thickness exceeds 5n+m, the processability during coating is poor, the workability is also reduced, and the advantages of the present invention are not improved in any way.

In addition, the composition of the present invention may include natural rubber, 5BR1EPR, EPD, etc. without departing from the purpose of the present invention.
Conventional fillers and additives such as synthetic rubbers such as M, waxes, plasticizers, fillers, pigments, antioxidants, and ultraviolet absorbers may be added.

As mentioned above, the concrete formwork/panel of the present invention is made of metal formwork/panel by coating with a mixed composition of a specific range of modified polyolefin resin and unmodified polyolefin resin.
It solves the problems of adhesion with the panel and releasability of concrete at the same time, and compared to conventional concrete formwork, it has the following advantages: ■ Easy coating process and good workability; ■ Good releasability. 1-The finished surface of the molded product is flat and beautiful, ■It is durable and robust, and the number of times it can be reused is greatly increased, so it can be used as a formwork.
Because it has excellent chemical resistance and weather resistance, it has many advantages such as no foreign matter on the surface of the formwork and panels, making it easy to manage the formwork and panels, and ■ being inexpensive.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1 to 5 and Comparative Examples 1 to 2 High-density polyethylene (M I 5,3 (1710 minutes, density 0.963 g/cc, trade name Nippatsu Stafrene E75)
0 (C), manufactured by Nippon Petrochemical Company), 100 parts by weight of anhydrous maleic M O, 20 parts by weight, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-30 as a baroxylide. , 05 heavy weight part was added and heated and kneaded in an extruder to obtain modified polyethylene.

The modified polyethylene and the high density polyethylene are first
The composition was homogeneously mixed in the predetermined proportions shown in the table, pulverized, and
I made it into powdered Metsuyupas.

A 5 pcc steel plate was coated with the powder to a thickness of 300 μm using an electrostatic coating method, and then heated and melted to form a coating film. The peel strength between the coating layer and the steel plate was measured and determined as adhesive strength. In addition, the releasability from concrete and the surface condition of concrete were evaluated. The results are shown in Table 1.

Measurements of coating conditions, adhesive strength, mold releasability from concrete 1, and surface condition of concrete were as follows.

<Coating conditions> A 5PCC steel plate was preheated to 200°C, electrostatically coated, heated at 200°C for 10 minutes, and then left to cool to obtain a coated steel plate.

Adhesive strength> Make a cut of 2.5 cm in the above-mentioned coated steel plate, peel off part of the polyethylene layer, and peel it off at 180° at a tensile speed of 50 mm/min.
The strength when peeled was measured and defined as adhesive strength.

<Mold releasability from Concrete 1 and surface condition of concrete> Concrete 1 prepared using a coated steel plate as a formwork by a known method was poured and solidified, and after concrete assimilation, formwork J was prepared by hand. : Ease of peeling (releasability when peeling) and finished concrete surface were observed and evaluated. J3, mold releasability from concrete and concrete
The evaluation method for the surface condition of items 1 to 1 was performed in four stages as follows.

■Mold releasability; ◎: Very good, ○: No resistance, △: Some resistance, ×: Resistance, ■Concrete surface condition◎: Glossy and very beautiful, O : Beautiful, Δ: Normal, ×: Lack of luster, with some unevenness.

As a result, Examples 1 to 5 had excellent adhesion and release properties from concrete, and the surface condition of the concrete was also good, whereas Comparative Example 1, which had a low content of modified polyolefin, had insufficient adhesive strength. , Comparative Example 7, which contains too much modified polyolefin, has poor mold releasability from concrete.
: There are problems with the surface condition of the concrete.

Examples 6 to 8 and Comparative Examples 3 to 6 30 parts by weight of modified polyethylene obtained by modifying the high density polyethylene used in Example 1 with the same formulation as in Example 1 and 70 parts by weight of unmodified high density polyethylene. mix the parts,
A composition was prepared so that the amount of maleic anhydride was 0.01, 1, 0, and 3.0% by weight (Examples 6 to 8), and the adhesive strength and mold release from concrete were determined in the same manner as in Example 1. The properties and surface conditions of Concrete 1~ were evaluated, and the results are shown in Table 1.

As a comparison, the high density poly:IT used in Example 1.

Only modified polyethylene obtained by modifying tyrene with the same formulation as in Example 1 was used, and maleic anhydride m was 0.
．． 01.1.0.3.0.6.0% monomer (Comparative Examples 3-6
), and the adhesive strength, releasability ti from concrete, and surface condition of concrete were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

As a result, Examples 6 to 8, in which the content of maleic anhydride was within the range of the present invention, had excellent adhesiveness and releasability from concrete, and the surface condition of Concrete 1 to 1 was also good. Comparative Example 3 had insufficient adhesive strength, and Comparative Examples 4-
No. 6 had good releasability from concrete No. 1 to J: and the surface condition of the concrete.

Example 9 Example 1 was prepared using the same composition as Example 2, in which the modified polyethylene 30ffi used in Example 1 was diluted with 70 parts by weight of unmodified polyethylene, but an aluminum plate was used instead of the steel plate. Similar evaluations were conducted and the results are shown in Table 1.

As a result, as in Example 2, it had excellent adhesion and releasability from concrete, and the surface condition to concrete 1 was also good.

Stop 1''LL Only modified polyethylene obtained by modifying the high-density polyethylene used in Example 1 with the same formulation as in Example 1 was used, and anhydrous maleic polyethylene was used. A composition was prepared containing 0.20% by weight of mff1, this composition was directly coated on an aluminum plate, and the same evaluation as in Example 1 was conducted. The results are shown in Table 1.

As a result, there were some difficulties in the releasability from concrete and the surface condition of concrete.

Claims (1)

[Claims] 1. 10 to 80 parts by weight of a modified polyolefin resin to which 5.0% by weight or less of (Δ) unsaturated carboxylic acid or its derivative has been added and (B ) A metal mold for concrete with good releasability, which is obtained by laminating a composition consisting of 90 to 20 parts by weight of an unmodified polyolefin resin and 0.01 to 4.0 parts by weight of an unsaturated carboxylic acid or its derivative. Frame/panel.