JPS6079919A - Continuous manufacture of phenol resin foamed body with skin layer - Google Patents

Abstract

PURPOSE:To obtain continuously the foamed body excellent in strength and heat resistance by a method in which two releasant members with an endless belt form are coated with curing resins during their turning movement, and after the phenol resin of foaming liquid resol type has been supplied on the curing resin on one releasant member, the curing resin on another releasant member is laminated thereon, and then they are foamed and cured. CONSTITUTION:While two releasant members 1, 1' of endless belt form are turned, they are coated with curing resin composition 6, 6' continuously. The phenol resin composition 15 of foaming liquid resol type is continuously supplied onto the coating film 8 of curing resin composition formed on one releasant member 1. Next, the coating film 8' of the curing resin formed on another releasant member 1' is inverted downward by turning movement of said releasant member and said film 8' is laminated on the phenol resin composition layer 16. After the layer 16 has been preheated and preliminarily foamed by a heater 17, it is sent to a heating zone 18, and then foamed and cured. The phenol resin foam 19 with skin layers 20, 20' may be continuously obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a phenolic resin foam having excellent flame resistance, fire resistance, and heat resistance, and having a skin layer with significantly improved friability, mechanical strength, and thermal insulation stability. Learn how to manufacture the body.

Phenolic resin foams have excellent flame resistance, fire resistance, and heat resistance, and because they do not emit smoke or toxic gas when burned, they have come to be used as building materials, furniture, and various industrial materials.

However, currently available phenolic resin foams are
It is extremely friable and extremely unsatisfactory in terms of strength. In addition, in recent years, phenolic resin foams with low thermal conductivity have become available by enclosing special gases such as Freon gas (trade name of DuPont); There was a drawback that the insulation performance was lost in a short period of time, that is, the stability of the insulation performance was poor.

As a manufacturing method for improving the drawbacks of conventional phenolic resin foams, a method for manufacturing phenolic resin foams having a skin layer has been proposed (Japanese Patent Application Laid-open Nos. Shojθ-/A7A7 and 1977-17-71). Publication No. 33, etc.).

However, in the method described in JP-A-30-17&7, phenolic resin is foamed on a suitable member coated with a surfactant that destroys bubbles, and the phenolic resin is foamed near the surface in contact with the member. It suppresses foaming and forms a skin layer. This method has the following drawbacks.

(1) Since the surfactant applied to the component remains on the surface of the foam, the surface of the resulting foam becomes sticky and easy to attract dirt and dust, which makes cleaning difficult. It is necessary to remove the surfactant by washing, etc., resulting in high postage.

(11) The skin layer formed by suppressing foaming is usually thin and has insufficient strength. Furthermore, since the skin layer is thin, the rigidity and strength of the entire foam (board) are insufficient.

(li+) The skin layer, that is, the unfoamed cured resin layer,
Naturally, since it is made of the same quality as the resol type resin used for the foam layer, the physical properties of the skin layer are limited by the performance of the resol type resin, and foams with skin layers with various different performances can be obtained. I can't do it.

(1v) The skin layer cannot be reinforced with an inorganic fiber reinforcing material or the like.

Furthermore, the method described in JP-A No. 37-4!71.3j is a method in which a foamable resol type phenolic resin composition is supplied to a closed mold that has been preheated to jO to 10OC and foam molded. However, this method also has the following drawbacks.

(a) Since the density of the foam and the thickness of the skin layer are determined by the mold temperature, it is not possible to freely produce a foam having a skin layer of any density and thickness.

(b) This method also has the same drawbacks as methods (7), (II) and (1v) described in JP-A-30-7G767.

The present inventors have conducted various studies to improve the above-mentioned deficiencies in conventional phenolic resin foams and methods for producing the same, and as a result, the present inventors have developed the method of the present invention, which allows excellent phenolic resin foams to be easily obtained. It has been reached.

In the continuous production method of the phenolic resin foam having a skin layer of the present invention, a curable resin composition containing a curing agent is continuously applied onto two endless belt-shaped release materials, and one release material is coated with a curable resin composition containing a hardening agent. A foamable liquid resol type buenol resin composition containing a foaming agent and a curing agent is continuously supplied onto the coating film of the curable resin composition formed in The layered material thus formed is continuously transferred to a heating zone along with the rotation of the release materials on both sides, and the curable resin composition is heated in the same heating zone. Curing the product and foaming and curing the foamable liquid resol type phenolic resin composition, before the foaming of the foamable phenolic resin composition is completed and before the curing of the curable resin composition is completed. This method is characterized by bringing the pre-foamed phenol resin layer into contact with the curable resin composition coatings disposed above and below, and completing the curing of both resins while maintaining the contact.

When using the method of the present invention, the material and thickness of the skin layer can be freely adjusted, and the friability is significantly improved.
A phenolic resin foam with excellent mechanical strength and little change in heat insulation performance over time can be easily obtained continuously and with high efficiency.

The release material used in the present invention has a heat resistance temperature of /
It is desirable to have a θOC or higher, and examples include polypropylene sheets, Teflon sheets, silicone resin coated papers, and the like. These release materials can be formed into a belt shape by themselves, but they usually lack strength as they are, so they can be removed by laminating or coating a suitable material with strength. It is desirable to form a material belt.

Examples of the resin for the curable resin composition in the present invention include resol type phenol resins, urethane resins, melamine resins, urea resins, and epoxy resins.

Since these curable resin compositions are well known to those skilled in the art,
The detailed explanation will be omitted. Further, since the curing agents for these resins are well known to those skilled in the art, detailed explanation thereof will be omitted. In the case of the curable resol type phenolic resin, the same one as the liquid resol type phenol resin for foam curing may be used, or a different one may be used without any problem.

The curable resin composition of the present invention may contain a fibrous reinforcing material, if necessary, to improve the strength of the skin layer. Particularly preferred reinforcing materials are inorganic fibers such as glass fiber and rock wool.

As the liquid resol type phenolic resin used in the foam curable liquid resol type phenolic resin composition of the present invention, any ordinary liquid resol type phenol resin can be effectively used. In addition, the acidic curing agents added to this include sulfuric acid, hydrochloric acid, phosphoric acid, para-toluenesulfonic acid,
Xylene sulfonic acid, benzene sulfonic acid, etc. are used. As a blowing agent, for example, 1:1c1 difluoromethane, trichlorochloromethane, butane, petroleum ether, etc. can be used. Furthermore, foam-curable liquid resol type phenolic resins include silicone oil,
It is desirable to incorporate a foam stabilizer such as dodecylbenzenesulfonic acid or polyalkylene ether polyol.

In producing the foam of the present invention, a fiber reinforcing agent is interposed between the curable resin composition coating film and the foamed curable resin composition layer in an amount that does not significantly impede contact between the two resins. As a result, the strength of the sysyan layer and, ultimately, of the entire foam can be improved. As a specific means for interposing the fiber reinforcing material, it is desirable to scatter an appropriate amount of the fiber reinforcing material onto the coating film of the curable resin composition, and in some cases, it is also possible to interpose a cloth-like fiber reinforcing material.
W This is 4 tables! Yu, iso,! - The most important materials are inorganic fibers such as glass fiber and rock wool.

Next, the present invention will be further described in detail based on FIG. 7 showing a typical embodiment of the manufacturing method of the present invention.

While continuously rotating the two endless belt-shaped release materials l and l' at the same linear speed, the mixing tank 2
and curable resin compositions 6 and 6I prepared in 2/
was continuously supplied onto the release materials/and//. In the mixing tank and tank, resin is continuously supplied through pipes 3 and 3', curing agent is continuously supplied through pipes 3 and PP, respectively, and a stirrer! A curable resin composition was continuously prepared by stirring and mixing with and da.

Resin compositions 6 and t' supplied on release materials l and /'
Since the thickness was not regulated by the doctor blades 7 and 7', it was continuously applied to a substantially uniform thickness, resulting in a curable resin composition coating film g'. It is desirable that the curable resin composition coating film I be precured by heating with a heater and a heater I.

Next, a foamable liquid resol-type phenolic resin composition was continuously supplied onto the resin coating g of the release material 1 from the preparation tank IO so that a layer of almost uniform thickness was formed.

In the formulation tank IO, resin is continuously supplied from pipe 1/2, foaming agent from pipe/2, and curing agent from pipe/3, and the mixture is stirred by a stirrer/1 to prepare a foamable resin composition. did. The foamable resin composition layer 16 formed on the resin coating r of the release material l can be formed naturally even at room temperature if the foaming agent contained is a low-boiling foaming agent, or by a heater in the case of a high-boiling foaming agent. By heating the release material 1 to an appropriate temperature using a device such as No. 17, it can be easily pre-foamed to form a pre-foamed product/6' with increased volume.

Next, the curable resin composition coating g' on the release material/', which is turned downward as the release material/' rotates, is superimposed on the pre-foamed body tA' together with the release material 7'. The multilayered material thus formed is transferred to the heating zone/g along with the rotation of the release material / and /l, and heated here at a predetermined temperature to form the curable resin composition layers g and g'. hardening,
When the foamable phenolic resin composition layer, that is, the pre-foamed body/4' is foamed and cured, a cured resin layer, that is, a skin layer 2 is formed on both the upper and lower surfaces of the phenolic resin foam layer/4'.
The resulting phenolic resin foam has a skin layer in which layers 0 and 20' are in close contact with each other. FIG. 1 shows a cutaway piece of the product foam of the present invention thus obtained.

Particular attention should be paid to the above-mentioned foaming and curing process before the foaming of the phenolic resin composition is completed and before the curing of the curable resin composition is completed. and upper and lower curable resin composition coatings g and g
', and the curing of both resins is completed while maintaining this close contact. If this condition is not fully satisfied, the phenolic resin foam layer/lito skin layer 20 and 20' will not adhere sufficiently, and the resulting foam will have poor brittleness and strength, which are disadvantages of phenolic resin foam. The deficiencies have not been sufficiently remedied.

The necessary foaming and curing conditions are determined by appropriately adjusting the distance between both sides of the material and 7', the temperature of the heating zone 7g, etc., depending on the composition and supply amount of the foamable phenolic resin composition to be supplied. easily obtained by

Next, the present invention will be explained in further detail by giving Examples and Comparative Examples.

Example/Two stainless steel belt conveyors t having a width of somm and whose surfaces were coated with Teflon were installed one above the other as shown in FIG. 2. The total length of the upper conveyor is 20m.
The total length of the lower conveyor was ztm. The width of the oven, that is, the heating zone, was 10 m.

The heating zone is kept at OC, and the linear velocity of each conveyor in front of the heating zone is set to 7 m/min. I kept it.

Moreover, the composition ratio of each resin used was as follows.

(1) Curable resin composition 50% sulfuric acid (curing agent) 10 〃 (:1) Foaming phenolic resin composition 10% sulfuric acid (curing agent) 4ttt Silicone oil (foam stabilizer) 2 〃 Shown in Figure 1 The above-mentioned curable resin composition was applied to a position o, s m from the left end of each of the upper and lower conveyors so that the coating thickness after passing through the doctor blade door and 7' would be Q, j; mm. Each was supplied continuously. Further, the foamable phenolic resin composition was applied to a location 7 m behind the supply point of the curable resin composition on the lower conveyor so that the thickness immediately after supply was approximately 7 m. ．． It was continuously supplied so as to have a uniform thickness of 1 mm (uniform thickness in the width direction).

Then, 7 m from the supply point of the foamable phenolic resin composition.
At the rear location, the resin layer formed on the upper conveyor was overlapped and brought into contact with the pre-foamed phenolic resin layer. The distance between both belt conveyors at this time was 39 mm. While maintaining this distance between the belts, the belts were passed through a heating zone (oven) to complete foaming of the foamable phenolic resin and curing of both resins.

Thus: Width soomm from the open exit.

Thickness: 3Qmm, skin layer thickness: 0. A phenolic foam with a skin layer of 13 mm was produced continuously. The physical properties of the foam were as shown in Table/.

Comparative Example Silicone oil (foam stabilizer) 2 10% sulfuric acid (curing agent) t The above foamed curable resin composition was 30 ctn in length and 30 ctn in width.
The mixture was placed in a Cm iron mold, heated at 6oc for 7 hours, and then cooled to obtain a foam without a skin layer with a thickness of 1'i23Qmnt. This foam was sliced to a thickness of 3 Qmm.

The physical properties of this foam were as shown in Table/.

Example 2 For the curable resin composition (:) in Example/,
A phenol resin foam having an epoxy resin as a skin layer was obtained using the following composition and turning it in the same manner as in the above. The physical properties of the product were as shown in Table 7.

Diglycidi g2g of bisphenol A) Evomate RX-3 (product name of Yuka Ciel Epoki 7 Co., Ltd.)! 011 (Curing agent) Table 7 Note) *・(1) was left at room temperature for 70 days after manufacture (2) was left at SOC for j months after manufacture As is clear from the results in Table 7, Examples The foam has significantly better physical properties than the foam of Comparative Example.

The main effects obtained by the production method of the present invention are summarized as follows.

(a) Since the surface friability is significantly improved by the skin layer, there is no risk of powder falling off.

(b) The skin layer significantly improves the rigidity and strength of the entire foam (board).

(c) Since the skin layer can be arbitrarily selected from rigid to flexible skin layers, it is possible to easily manufacture the optimal skin layer depending on the application.

(d) The disadvantage of high water absorption of phenolic resin foam is significantly improved by the skin layer.

(E) When applied to the production of recently developed phenolic resin foams with low thermal conductivity that confine gases with low thermal conductivity (e.g. Freon gas, etc.), it will take a long time to manufacture ordinary 7-technol resin foams. As the temperature increases, the low thermal conductivity gas dissipates and is replaced by air, but the foam of the present invention
Since the skin layers on both the upper and lower surfaces prevent low thermal conductivity gas from escaping, there is little deterioration of thermal conductivity over time.

[Brief explanation of drawings]

Fig. 7 is a cutaway and partially cutaway schematic diagram showing the entire apparatus during the production of foam according to the manufacturing method of the present invention, and Fig. 2 is a perspective view of a cutaway piece of the foam product of the present invention. . Each symbol in the figure corresponds to the following. i, i'... Conveyor pel li4 [material λ, 2'
...Curable resin composition preparation tank, g'...Curable resin composition coating film 10 ...Foamable phenolic resin composition preparation tank/6...Foamable phenolic resin composition layer 76'
... Pre-foamed phenolic resin composition layer (phenolic resin pre-foamed material) 7g ... Heating zone/ta ... Phenol resin foam layer 0.20'... Skin layer Patent applicant Mitsubishi Yuka Corporation

Claims (1)

[Claims] /) While rotating two endless belt-shaped release materials, a curable resin composition containing a curing agent is continuously applied onto each release material, and the cured resin composition formed on one of the release materials is A foamable liquid resol type phenolic resin composition containing a blowing agent and a curing agent is continuously supplied onto the coating film of the foamable liquid resol type phenolic resin composition, and the foamable liquid resol type phenolic resin composition layer is then , the curable resin composition coating formed on the other release material is turned downward as the release material rotates, and is overlapped with the release material, so that the multilayered product thus formed is rotated by the re-release material. The curable resin composition is cured and the foamable liquid resol type phenolic resin composition is foamed and cured in the same heating zone. Before foaming of the product is completed and before curing of the curable resin composition is completed, the pre-foamed phenolic resin layer and the curable resin composition coating films disposed above and below are brought into contact and the contact is maintained. 1. A method for continuously producing a phenolic resin foam having a skin layer, characterized in that curing of both resins is completed in a state in which both resins are cured.