JPH0316899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a phenol foam complex. More specifically, the present invention relates to a method for producing a phenol foam composite containing aggregate particles.

Conventionally, powdered foamable phenolic resin compositions have been prepared by mixing lightweight aggregate particles such as plastic foamed (or unfoamed) particles and inorganic particles with uncured novolac type phenol-formaldehyde resins, curing agents, and blowing agents. There is a known method for producing a phenol foam composite by filling the mixture into a predetermined mold and heating and foaming it to harden the mixture after mixing.

However, in such a manufacturing method, no matter how uniformly the aggregate particles and the expandable phenolic resin composition are mixed before foaming and curing, it is difficult to produce a phenol foam composite in which the aggregate particles are uniformly dispersed. It was difficult to obtain.

This is because the balance between the aggregate particles and the composition before foaming and curing may be disrupted due to foaming and expansion of the composition during foaming and curing, and the aggregate particles and composition may not be balanced during or after filling into the mold. This is thought to be due to natural non-uniformity due to differences in specific gravity and shape. This tendency was particularly strong when aggregate particles with a particle size of 2 mm or more were used, and the larger the particle size, the more pronounced it became.

In addition, in this method, when brittle aggregate particles such as expanded pearlite particles are used, there is a problem that the aggregate particles are crushed or damaged during mixing.

The present invention has been made in view of such conventional problems, and one object thereof is to provide a manufacturing method that can easily produce a phenol foam composite in which aggregate particles are uniformly dispersed. It is something.

The inventors of the present invention first conducted various studies on the mixing method of aggregate particles and a foamable phenolic resin composition, but the above-mentioned problems could not be solved. As a result of further research, the inventors found that a uniform phenol foam composite was easily produced by foaming and curing aggregate particles while being loaded on a layer of the resin composition having a substantially uniform thickness. This invention was achieved by discovering the surprising fact that it can be absorbed, and by conducting further studies.

Thus, according to the present invention, a granular foamable phenolic resin composition comprising an uncured novolak type phenol-formaldehyde resin, a curing agent, and a decomposable blowing agent is introduced into a mold, and is spread almost onto the bottom surface of the mold. A state in which a layer of the composition is uniformly formed, and then aggregate particles are loaded onto the composition layer without being mixed with the composition powder and filled into a mold, and the mold is closed. Provided is a method for producing a phenol foam composite, which comprises foaming and curing a foamable phenolic resin composition by heating at .

The most characteristic feature of this invention is that the aggregate particles and the expandable phenolic resin composition are subjected to foam molding in a separated state without being substantially mixed.

The above-mentioned uncured novolac type phenol-formaldehyde resin refers to a resin obtained by reacting phenol-formaldehyde in the presence of an acid under conditions where the former is in excess, and is called a novolac.

Suitable curing agents for the resin include compounds that can decompose to produce aldehydes when heated, such as hexamethylenetetramine, performaldehyde, trioxane, cyclic formal, and the like. Among these, hexamethylenetetramine is preferable because it can efficiently cure by generating aldehyde and ammonia during heating in the presence of condensed water, and can increase the foaming efficiency of the blowing agent described below. It is a drug.

As the blowing agent, decomposable blowing agents that can decompose in the composition and generate gas during heat curing are suitable, such as dinitrosopentamethylenetetramine, benzenesulfonyl hydrazide, azobisisobutyronitrile, and azodicarbonate. Amide, para-toluenesulfonyl hydrazide, ammonium carbonate, sodium bicarbonate, and the like.

The foamable phenolic resin composition used in this invention is a granular mixture consisting of the uncured novolak type phenol-formaldehyde resin, a curing agent, and a blowing agent. The appropriate amount of curing agent added to Novolak is 5 to 20 parts by weight/100 parts by weight,
9 to 12 parts by weight/100 parts by weight is preferred. The amount of the foaming agent added is suitably 1 to 10 parts by weight/100 parts by weight, preferably 5 to 6 parts by weight. Note that various other additives may be added to this composition, for example, fillers such as clay may be added. However, such additives are 5 parts by weight/100
It is preferable that the amount is less than parts by weight. It is preferable that these be mixed as uniformly as possible. Usually, an uncured novolak type phenolic resin is melted at 60 to 90°C, a curing agent and a blowing agent (and optionally additives) are added and mixed, and then cooled to form a mixture, which is then powdered. It is appropriate to prepare it by crushing it into a shape. Of course, such a foamable phenolic resin composition may be a commercially available product.

On the other hand, as the aggregate particles used in this invention, inorganic and/or organic granules are used. Specific examples of these include inorganic particles such as perlite, shirasu balloons, glass balloons, glass foam particles, viscous foam particles, viscous foam particles, cement particles, and stone particles;
Examples include organic particles such as synthetic resin particles and foamed synthetic resin particles. In addition, typical base resins for synthetic resin particles and foamed particles include phenolic resins, polystyrene resins, polyolefin resins, etc., and resins with heat resistance of 100°C or higher are usually suitable, although it depends on the application. . An example thereof is styrene-maleic anhydride copolymer resin.

However, as the above-mentioned aggregate particles, wood powder particles, paper particles, organic-inorganic composite particles, metal particles, etc. can also be used depending on the case.

The particle size of these aggregate particles is preferably 2 mm or more, and preferably 2 to 25 mm. If the particle size is less than 2 mm, there is a risk that the dispersion will be uneven in terms of balance during foaming, and
There is no need to use aggregate larger than 25mm for normal applications.

In this invention, first, the powdered foamable phenolic resin composition described above is introduced into the bottom surface of a mold such as a metal mold so as to form a substantially uniform layer. This introduction should be adjusted to give a layer of as uniform thickness as possible. The amount of such a composition layer to be introduced can be determined mainly depending on the volume of the mold, and it also depends on the filling ratio of aggregate particles, but basically, it is necessary to determine the amount of the composition layer introduced into the entire mold during foaming. An amount that can expand is sufficient. This process is shown in FIG.
In the figure, 1 indicates a foamable phenolic resin composition layer, 2 indicates a mold, and 3 indicates a release paper. Next, desired aggregate particles 5 are placed on the composition layer 1 and filled into the cavity 4. At this time, it is necessary to stack the aggregate particles 5 and the composition so that they do not mix as much as possible. This process is as shown in FIG. After the aggregate particles 5 are filled onto the composition layer 1 in a separate layer state, the above-mentioned 6 is set, the mold is closed, and heating is performed. Heating may be carried out at a temperature that allows the composition itself to foam and harden, and is usually carried out at 120 to 180°C for about 3 to 20 minutes. By such heating, the composition 1 at the bottom of the mold undergoes a melting process and hardens while foaming. At this time, the aggregate particles 5 that are gradually foamed upward are
The cavity is filled by expanding through the individual voids in the cavity. Then, a phenol foam composite shown in FIG. 4 in which each aggregate particle is uniformly bonded and integrated with the phenolic resin foam layer 1' is formed in the mold.

From the viewpoint of obtaining a uniform composite, the degree of filling of the aggregate particles into the cavity 4 is preferably such that 70 to 100% of the voids are filled, although it depends on the particle size. If it is less than 70%, it is difficult to obtain a uniform composite. However, when adjusted to 30% to 70%, it is difficult to obtain a composite in which the aggregate particles are uniformly dispersed throughout, but the aggregate particle bonding layer and the foam layer are separated and integrated. A complex can be obtained. Therefore, when such a composite is intended, that is, a composite consisting of a uniform foam layer on one side and a uniform aggregate particle bonding layer on the other side, the degree of filling is adjusted as described above. However, if it is less than 30%, it is not suitable to obtain such a two-layered product, which becomes completely non-uniform and similar to that obtained by conventional methods.

Although a mold that can be closed as described above is used as the molding mold, it is appropriate to use a mold that can at least discharge air inside the cavity during foaming.

The phenol foam composite of the present invention obtained in this manner is useful for applications requiring fire resistance, such as heat insulation materials, panel core materials, and ceiling materials. The formed phenol foam composite board can be used as a building exterior board (sizing board) by laminating it with a metal plate.
It can be suitably used as

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereby.

Example 1 Dimensions inside the mold: height 25mm, width 300mm x 300mm
A mold with a flat bottom and a flat lid that can be opened and closed was used.

A release paper was placed on the bottom of the mold, and then 100 g of the foamable phenolic resin composition was spread to a uniform thickness to form a composition layer. The composition used in this case was a powder obtained according to the following formulation, and the thickness of the composition layer was about 1 mm.

[Expansible phenolic resin composition]

(a) Uncured novolac type phenol-formaldehyde resin [melting point 81℃, gelation time 150℃ 76 seconds
100 mesh pass remaining 0.5%) ...100 parts by weight (b) Hexamethylenetetramine (hardening agent)
...10 parts by weight (c) Dinitropentamethylenetetramine (foaming agent) ...5 parts by weight *The above (a), (b), and (c) were mixed in a roll mixer at 80℃, 5
100 mesh pass powder was mixed and ground for minutes and then placed as aggregate particles in the mold with an average particle size of 5.3 mm.
200g of pearlite particles (trade name: Fuyolite, manufactured by Fuyolite Kogyo Co., Ltd.) were loaded onto the above composition layer without being substantially mixed with the composition, and the mold was filled almost completely (filling degree: 100%). ), close the lid, and heat at 150℃ and press pressure 40Kg/ ^cm2 .
Press heating was performed for a minute. The mold was removed from the press, and the phenol foam composite was released from the mold.

In the obtained phenol foam composite, pearlite grains are uniformly dispersed throughout the phenol foam, and when cut, the voids between the grains (porosity 40
%) was completely filled with phenolic foam. Moreover, no defects were observed in the pearlite grains.

The physical properties of this composite include an apparent density of 144Kg/cm ³ ,
Bending strength: 8.3Kg/cm ² , Compressive strength (at 5% strain): 7.6Kg
f/ ^cm2 .

Example 2 A composite was produced in the same manner as in Example 1, except that 400 g of foamed glass particles (trade name: Cellobeads, Toyota Boshoku Co., Ltd.) with an average particle size of 3.7 mm were used as aggregate particles.

The obtained phenol foam complex was prepared in Example 1.
Similarly, the foamed glass particles are uniformly dispersed throughout the foamed layer, and the voids between the particles (porosity 40%)
was completely filled with phenolic form.

The physical properties of this composite include an apparent density of 222Kg/m ³ ,
Bending strength: 12.8Kgf/cm ² , Compressive strength (at 5% strain)
It was 13.7Kgf/ ^cm2 .

Example 3 Filling amount of pearlite grains is 150g (filling degree 75%)
A composite was produced in the same manner as in Example 1 except for the following.

In the obtained phenol foam composite, pearlite grains were almost entirely dispersed, and the spaces between each grain were completely filled with phenol foam. However, compared to Example 1, the gaps between grains were more uniform.

The physical properties of this composite include an apparent density of 135Kg/m ³ ,
Bending strength: 7.61Kgf/cm ² , Compressive strength (at 5% strain)
It was 6.9Kgf/ ^cm2 .

Example 4 Filling amount of pearlite grains is 100g (filling degree 50%)
A composite was produced in the same manner as in Example 1 except for the following.

The voids between pearlite grains in the obtained phenol foam composite were filled and bonded with phenol foam, but such a composite layer was only in the upper layer of the composite, and the lower layer was a phenol foam layer that did not contain pearlite grains. Although it was integrated, it was divided into layers. However, no density difference was observed between the upper and lower layers of this composite.

Comparative Example 1 A composite was produced in the same manner as in Example 1, except that pearlite particles and a foamable phenolic resin composition were mixed and filled.

When the pearlite grains and the expandable phenolic resin composition were mixed, some of the pearlite grains were lost and pearlite powder was generated. Then, I intentionally filled the mixture to make it as uniform as possible to prevent the mixture from becoming unequal.
The obtained phenol foam composite was non-uniform, with some parts having only a phenol foam layer, and air pockets partly occurring inside the composite. This air pocket is thought to occur because the foamable phenolic resin composition is heated and foamed from the upper and lower surfaces, so there is no space for air to escape.

As described above, according to the production method of the present invention, a uniform phenol foam composite can be easily produced. Moreover, it is advantageous in terms of operation because it does not require the mixing operation of aggregate particles and a foamable resin composition, which has been frequently used in the past, and even when brittle aggregate particles are used, no crushing or cutting occurs. Furthermore, by adjusting the usage ratio of aggregate particles, etc., it is also possible to produce special composites with separate layers.

[Brief explanation of drawings]

1 to 4 are schematic diagrams including cross sections sequentially explaining the steps of the manufacturing method of the present invention. 1... Foamable phenolic resin composition layer, 1'...
... Phenol resin foam layer, 2 ... Mold, 3 ... Release paper, 4 ... Cavity, 5 ... Aggregate particles, 6
...upper mold.

Claims (1)

[Scope of Claims] 1. A powdered foamable phenolic resin composition consisting of an uncured novolac type phenol-formaldehyde resin, a curing agent, and a decomposable foaming agent is introduced into a mold, and is spread almost uniformly onto the bottom surface of the mold. After forming a layer of the composition in a similar manner, aggregate particles are loaded onto the composition layer without being mixed with the composition and filled into a mold, and the mold is closed. A method for producing a phenol foam composite, comprising foaming and curing a foamable phenolic resin composition by heating. 2 The degree of filling of aggregate particles is
30 to 100% of the manufacturing method according to claim 1. 3 The degree of filling of aggregate particles is
70 to 100% of the manufacturing method according to claim 2. 4. The manufacturing method according to any one of claims 1 to 3, wherein the particle size of the aggregate particles is 2 mm or more. 5. The manufacturing method according to claim 4, wherein the aggregate particles have a particle size of 2 to 25 mm.