JPH04114976A - Production of particle coated with phenolic resin - Google Patents

Abstract

PURPOSE:To form an incombustible building material having excellent flexibility from inorganic powder by successively adding a novolak phenolic resin, a polyvinyl acetal and an aqueous solution of hexamethylenetetramine to heated inorganic powder. CONSTITUTION:(a) A phenolic compound is made to react with (b) an aldehyde in the presence of an acid catalyst to obtain a novolak phenolic resin (B) which is a precondensate further polymerizable in the presence of a curing agent accompanying crosslinking reaction. The subject particle can be produced by adding 10-100g of the component B and (C) 5-25wt.% (based on the component B) of a polyvinyl acetal having a polymerization degree of 200-600 and an acetalization degree of 60-70mol% in separated state or in the form of a mixture of both components to (A) 1 liter of inorganic powder heated at or above the temperature to effect sufficient melting and flowing of the component B, e.g. at 120-170 deg.C under stirring to effect the sufficient dispersion of the components and adding (D) 5-20wt.% (in terms of solid, based on the component B) of an aqueous solution of hexamethylenetetramine to the dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to resin-coated particles that are nonflammable and can be processed into building materials with excellent mechanical properties, particularly flexibility.

(Prior Art) In recent years, with the diversification of buildings, the performance of building materials has improved, and as a result, many plastic building materials have come to be used as interior and exterior materials. A series of plastic building materials are superior to cement-based building materials in terms of weight, heat insulation, environmental resistance against humidity and frost damage, decorative properties, and ease of production and processing, but they are also flammable. In the event of a fire, it is easy to spread and the smoke of toxic gas etc. is also significant.

In order to improve these drawbacks, the amount of synthetic resin used should be kept to the minimum necessary for molding building materials, flame retardants such as aluminum hydroxide should be added, and phenolic resin, which is a low-smoking synthetic resin, should be used. Measures such as these are being attempted.

For example, Japanese Patent Application Laid-Open No. 56-62143 discloses a method of curing fly ash, pumice, and glass am with phenolic resin to use as a building material, but in order to achieve nonflammability with this method, the phenol resin concentration must be extremely high. It must be kept in a small amount, and in this case there is a drawback that the deflection tolerance of the molded article is significantly reduced.

(Problems to be Solved by the Present Invention) The present invention has been made in order to provide a method for producing resin-coated particles that can eliminate the above-mentioned conventional drawbacks.

That is, an object of the present invention is to provide a method for producing phenolic resin-coated particles that are nonflammable and can be processed into building materials with excellent mechanical properties, particularly flexibility (deflection tolerance performance).

Each 9. Adding (1) 10 to 100 y of novolak type phenolic resin to 1 liter of heated inorganic powder and granular material N
, +21 polyvinyl butyral, and (3) adding an aqueous hexamethylenetetramine solution, thereby achieving the above object.

In addition, in the above-mentioned steps of fil to (3), it is preferable to mix (stir) as appropriate after adding the additive.

The inorganic powder and granules referred to in the present invention are not particularly limited, and include, for example, sand, silica sand, natural rock granules, diatomaceous earth, whitebait, alumina, clay, kaolin, talc, and other natural sands and minerals, as well as ceramics, porcelain, and glass. Artificial materials and waste such as powder, coal ash (fly ash), other hydroxides of aluminum, calcium, magnesium, etc., or those containing carbonates, sulfates, silicates, or their crystal water, and Perlite, vermiculite, glass balloons, shirasu balloons, coal ash balloons, ceramic balloons, etc. are preferably used as lightweight particles. The shape, particle size, particle size distribution, etc. of these inorganic powders are not particularly limited.

The novolac type phenolic resin that can be used in the present invention is an initial condensate obtained by reacting phenols and aldehydes in an acid catalyst, and the initial condensate is obtained by reacting a phenol with an aldehyde in the presence of a curing agent. It means that polymerization can further proceed while accompanied by a crosslinking reaction. Phenols mainly refer to phenols, but they also refer to resins derived from novolac-type modified phenol resins, such as cresol and its isomers, xylenol and its isomers, alkylphenols, cashew oil, and bisphenols. It is at least one kind selected from the following. Further, aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, furfural, higher aldehydes, and the like. Furthermore, acid catalysts include strong acids such as oxalic acid, sulfuric acid, para-toluenesulfonic acid, 03% Zn, Cd1Fb,
It refers to a metal salt catalyst such as Co or Ni.

The composition ratio of the phenolic resin used in the present invention is:
The number of copies is limited to 10 to 100 f per liter of inorganic powder, and if it is less than 102, the strength of the molded product will be low and it will not have satisfactory mechanical properties as a building material. Furthermore, if the material is used at a temperature exceeding 00y, although the mechanical properties are improved, it is no longer possible to ensure nonflammability.

The polyvinyl acetal that can be used in the present invention is a resin obtained by acetalizing polyvinyl alcohol, but its chemical composition is not particularly limited. The aldehyde species is mainly butyraldehyde, but may also be coacetalized with other aldehyde species such as formaldehyde, acetaldehyde, hexylaldehyde, benzaldehyde, etc. In order to achieve the object of the present invention, it is preferable that the degree of polymerization is in the range of 200 to 600 and the degree of acetalization is in the range of 60 to 70 mo1%.

The concentration of the polyvinyl acecool used in the present invention is preferably 5 to 25 wt% based on the phenol resin, and 5 wt%
If it is less than 4Qwt%, the effect of imparting flexibility to the final molded product is poor, and if it exceeds 4Qwt%, not only the rigidity of the molded product decreases, but also smoke emission during combustion increases significantly.
Nonflammability or flame retardancy becomes difficult to achieve. More preferably, it is 10 to 3 Qwt%.

In the present invention, in order to coat the above-mentioned inorganic powder with the phenol resin and the polyvinyl acecool, for example,
■Pour the heated inorganic powder into a stirrer, ■Add a predetermined amount of both resins while stirring, either separately or after mixing them, to fully disperse them.■Next, add the hexamethylenetetramine aqueous solution. A common method is to further stir the mixture.

The temperature of the inorganic powder at the time of resin injection is at least the temperature at which the phenol resin sufficiently melts and flows, for example 120 -
170℃ is tricky. In addition, the temperature of the powder and granules when adding the hexamethylenetetramine aqueous solution is preferably 100 to 140°C; if it exceeds this temperature, the hexamethylenetetramine decomposes to form formalin, and the curing of the phenol resin progresses, resulting in When this is molded, the strength of the molded product tends to decrease.

Hexamethylenetetramine later acts as a curing agent for the novolak resin (when the coated particles are aged). Paraformaldehyde, resol, and the like are other conceivable curing agents that have such an effect, but hexamethylenetetramine is superior in terms of handling stability. The weight of hexamethylenetetramine that can be effectively used is usually 5 to 2 Qwt% in solid content based on the phenol resin, and it is diluted 5 to 15 times with water and added as an aqueous solution.

In order to obtain the coated particles of the present invention, a coupling agent that improves the interfacial adhesion between the inorganic powder and the thermosetting resin may also be used for the purpose of improving the strength of the molded product. Effective coupling agents include aminosilane-based and epoxysilane-based coupling agents, which may be processed into inorganic powder in advance or mixed directly into the phenol resin.

Furthermore, a lubricant may be added for the purpose of improving the fluidity of the particle group, preventing blocking, and improving storage stability. As effective lubricants, higher fatty acid metal salts such as calcium stearate, higher fatty acid amides, polyolefin wax, paraffin wax, etc. are preferably used.

In addition, additives and fillers such as heat stabilizers, antioxidants, antistatic agents, fungicides, flame retardants, and inorganic fibers as reinforcing fillers are used to significantly impair light weight, mechanical properties, and nonflammability. It can be used as appropriate within the range.

The phenol resin-coated particles provided by the present invention can be heat-molded into any shape by any method to form a composite molded product, which can be effectively used for, for example, building materials.

In the present invention, any method can be used to obtain this molded body.

(Function) Phenolic resin is an excellent flame-retardant resin that emits extremely little smoke when burned. The composite molded article obtained from the resin-coated particles of the present invention is composed of a large amount of inorganic material and a very small amount of phenolic resin, and therefore has excellent flame resistance.

In the present invention, polyvinyl acecool is blended with the phenol resin for the purpose of imparting flexibility.

The blending effect with polyvinyl acecool is maximized through compatibilization, but ordinary simple blending between resin powders is insufficient. In the production method of the present invention, both resins are sufficiently melted and kneaded using inorganic powder as a medium.
Compatibilization of both resins is achieved, and as a result, a composite molded article imparted with flexibility is obtained. Furthermore, the present invention is significant in that this can be done in a solvent-free dry process.

(Example) Example 1 Granular calcium carbonate (pulverized product, average particle size 190 μm) preheated to about 150°C in an experimental speed mixer.
1 liter, 40 P of novolac-type phenol hatsumode (BRP572 A, manufactured by Showa Fumoto Bunsoku Co., Ltd.), and 10 y of polyvinyl acecool (S-LEC BL-1, manufactured by S. Suikagaku Co., Ltd., PVB in the table) were added. After stirring and kneading for 1 minute, a solution of 6y of hexamethylenetetramine dissolved in 50y of water was added, and the mixture was stirred until the calcium carbonate lumps collapsed. Next, calcium stearate 1y was added and after stirring for 30 seconds, the mixture was taken out from the mixer to obtain a novolac type phenol resin-coated calcium carbonate.

Next, this novolac-type phenolic resin-coated calcium carbonate was placed in a metal mold (250 x 250
The mixture was filled into a cup (12 m x 12 m and 150 x 100 x 4 fl), heated in a heating furnace at 1.80°C for 15 minutes, and then the molded body was taken out from the core mold.

Bulk specific gravity, bending strength, bending 10- Table 1 shows the results of evaluating the elastic modulus and nonflammability.

The bending test was conducted in accordance with JIS K 7203 using a test piece measuring 80 x 110 x 4 prepared from the molded product. In addition, the nonflammability test is based on the Ministry of Construction Publication No. 18 based on the Building Standards Act.
28 (December 28, 1970), 40 x 40
Test pieces of 50 tg and 220 x 220 x 12 m were prepared.

Example 2 A novolac type phenol resin-coated calcium carbonate was prepared in exactly the same manner as in Example 1 except that the weight of novolac type phenol lNB11 was 80y1, polyvinyl butyral was 20y1, hexamethylenetetramine and water were 12y and 100y, respectively, and A molded body was obtained and an evaluation test was conducted. The results are also shown in Table 1.

The weight of the novolac type phenolic resin shown in Table 1 is 4.
oy is @ and 120y, polyvinyl butyral is opsslla and 30y hexamethylenetetramine is 6y @ clause F, and 18 no, water is 5oyJ! Ifl'
One type of novolak type phenol resin-coated calcium carbonate was prepared in exactly the same manner as in Example 1 except that ff'@ and 150y were used, molded bodies were obtained, and evaluation tests were conducted on each. The results are shown in Table 1.

Comparative Example - Powdered thermosetting novolac type phenolic resin (Showa Polymer BRP) was added per liter of the above calcium carbonate.
522Z-40F and the same polyvinyl butyral 6y as in Example 1 were blended and mixed at high speed in a mixer. Using a mixed powder obtained, a molded product was obtained by the same molding method as in Example 1, and an evaluation test was conducted. went. The results are shown in Table 1.

(The following is a blank space) Table 1 The phenolic resin-coated particles of the present invention are of high practical value.

Claims (1)

[Claims] Includes the steps of (1) adding 10 to 100 g of novolac type phenolic resin, (2) adding polyvinyl acetal, and (3) adding hexamethylenetetramine aqueous solution per liter of heated inorganic powder. A method for producing phenolic resin-coated particles characterized by the following.