JPH07300535A - Thermosetting foamable resin composition - Google Patents

Abstract

PURPOSE:To provide a foamable resin compsn. which is free from sagging in coating or from slip out of the position of sheets in sticking, completely fills openings of hollow parts, pipes, etc., improves the structural strength of hollow parts, etc., and can give them excellent soundproof, vibrationproof, and heat insulation properties, etc. CONSTITUTION:This compsn. contains a thermosetting resin, an org. blowing agent, a thixotropic agent, and fine hollow particles and has a density of 1.0g/cm<3> or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, hollow parts formed of thin plate members such as doors of automobiles and various pipes, by filling the voids thereof to improve the structural strength, and at the same time, to prevent noise and vibration. The present invention relates to a thermosetting foamable resin composition used for imparting properties such as heat resistance and heat insulation.

[0002]

2. Description of the Related Art In automobiles, home electric appliances, industrial machines, etc., the parts thereof are hollow because they are made of a thin plate member in order to reduce the weight of the products. Examples of such hollow parts include automobile doors, roofs, fenders,
Examples include trunks and various pipes. However, from the viewpoint of safety and comfort, products such as automobiles are required to have a certain level of structural strength, soundproofing, vibrationproofing, heat insulating properties, and the like. Therefore, in the above hollow parts and the like, a reinforcing member made of an iron member and a foam filling member for filling the hollow portion are used.

As the foam filling member, a rubber type foam sheet has been conventionally used. By sticking this rubber-based foamed sheet to the voids such as the hollow parts, the products such as automobiles are provided with soundproofing, heat insulating and vibration damping properties. However, this rubber foam sheet
Since it is flexible, it cannot be expected to improve the structural strength of the above components. Therefore, recently, a urethane-based two-component curable expandable resin composition and a sheet-like or putty-like thermosetting expandable resin composition have been used as a reinforcing material.

The above-mentioned urethane-based two-component curable foamable resin composition is a liquid composition prepared by mixing a two-component curable urethane resin with a foaming agent. This liquid resin composition is, for example, applied to the inner peripheral surface of a thin plate member of an automobile door to cure it, and is expanded and expanded by the action of the foaming agent to fill the voids of the door or the like. If this urethane-based two-component curable resin composition is used, the structural strength of parts will be improved by the action of the cured product, and since the cured product is foamed, it will be sound-proof, heat-insulating, and vibration-proof. It becomes possible to add the characteristics of. However, this urethane-based two-component curable resin composition has a problem of dripping during coating.
That is, since the resin composition is in the liquid state as described above, when the resin composition is applied to the standing thin plate member or the like, the resin composition flows by its own weight. Therefore, the use of this urethane-based two-component curable resin composition is limited to the surface to be coated in a horizontal state, a bag-shaped hollow component such that the liquid does not flow out even in a standing state, and the like.

On the other hand, the thermosetting foamable resin composition is a mixture of a thermosetting resin and a heating foaming agent, and is used after being molded into a putty shape or a sheet shape. Since the thermosetting foamable resin composition has excellent rigidity, the use of the thermosetting foamable resin composition can remarkably improve the structural strength of the hollow parts and various pipes. Further, also in this resin composition, since the heat-foaming agent is used, the cured product foams and expands, resulting in sound insulation, heat insulation,
It is also possible to impart vibration-proof properties.

[0006]

However, even in such a high-performance thermosetting foamable resin composition, when used for standing hollow parts, various pipes and the like, the above urethane-based two-component curable resin composition is used. As with objects, problems such as liquid dripping, sheet misalignment, and peeling occur. That is, when a putty-like thermosetting foamable resin composition is used, it cannot be applied uniformly due to the flow of the resin composition due to its own weight, and in the case of a sheet-shaped resin composition, a sheet is used. After sticking, slippage or peeling occurs due to its own weight. This problem becomes serious especially when the width of the void is 20 to 30 mm or more. Even if the thermosetting foamable resin composition that is unevenly coated or that is displaced or peeled off is heated and foam-cured, it is possible to sufficiently fill the voids of the hollow parts and various pipes. It is not possible to improve the desired structural strength,
It is not possible to obtain properties such as soundproofing, heat insulation, and vibration isolation.

In order to solve this problem, it can be considered to add a thixotropy-imparting agent to the thermosetting foamable resin composition to increase the viscosity of the resin composition. However, when the viscosity of the resin composition is increased, the foaming property is hindered and the properties such as soundproofing are deteriorated. Therefore,
The thixotropy-imparting agent cannot be blended in such a high proportion as to effectively prevent dripping of the resin composition or deviation or peeling of the sheet.

The present invention has been made in view of the above circumstances, and does not cause liquid dripping during coating or sheet misalignment or peeling during sticking, and does not cause voids in hollow parts or various pipes. PROBLEM TO BE SOLVED: To provide a thermosetting foamable resin composition which can be sufficiently filled to improve the structural strength of the above hollow parts and various pipes and to impart excellent soundproofing, vibrationproofing and heat insulating properties to them. Is its purpose.

[0009]

In order to achieve the above object, the thermosetting foamable resin composition of the present invention contains the following components (A) to (D) and has a resin composition having a density of The configuration is set to 1.0 g / cm ³ or less. (A) Thermosetting resin. (B) Organic foaming agent. (C) A thixotropic agent. (D) Micro hollow particles.

[0010]

In the thermosetting foamable resin composition, the present inventors conflict with the prevention of liquid dripping or sheet misalignment due to the weight of the resin composition during coating or sticking, and improvement of foamability. A series of studies were conducted to solve the problems at the same time. In the process, as a means for solving the above problems such as dripping,
The idea was to combine not only the thixotropy-imparting agent but also the adjustment of the density of the resin composition. Based on this idea, when the density of the resin composition before curing is set to a specific value or less, and the thixotropy-imparting agent is blended in a low proportion that does not impair the foamability of the resin composition, this putty-like or sheet-like It has been found that even if the thermosetting expandable resin composition is coated or adhered to voids such as hollow parts and pipes in an upright state, dripping or sheet slippage or peeling due to its own weight does not occur. . Then, when the thermosetting foamable resin composition adhered or the like is heated, the thermosetting foamable resin composition is sufficiently cured and foamed and expanded in the voids of the hollow component to fill the voids without any gaps. As a result, the structural strength of hollow parts such as automobile doors and various pipes is significantly improved, and at the same time, it is possible to impart excellent properties such as soundproofing, vibration damping, and heat insulating properties.

Next, the present invention will be described in detail.

The thermosetting foamable resin composition of the present invention comprises a thermosetting resin (component A), an organic foaming agent (component B), a thixotropic agent (component C) and fine hollow particles (component D). contains.

The thermosetting resin (component A) is the main component of the thermosetting foamable resin composition of the present invention.
The thermosetting resin is not particularly limited, and examples thereof include various epoxy resins such as glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type, alicyclic epoxide type and modified epoxy resins thereof. , Melamine-based resins, polyester-based resins, phenol-based resins, urea-based resins, etc., and they may be used alone or in combination of two or more. Among these, the above-mentioned epoxy resin and its modified epoxy resin which are excellent in adhesiveness to metal are preferable.

The thermosetting resin (component A) contains
Usually, a heat-activated curing agent (hereinafter referred to as “curing agent”) that exerts a curing action by heating (80 to 200 ° C.) is added. Examples of the curing agent include epoxy resin curing agents such as dicyandiamide, 4,4'-diaminodiphenylsulfone, phenol, various acids or acid anhydrides, and polyamide. And a hardening accelerator may be mix | blended with the said thermosetting resin (A component).
As the curing accelerator, imidazole derivatives such as 2-n-heptadecylimidazole, isophthalic acid or adipic acid dihydrazide, guanidine series, N, N-dialkylthiourea derivatives and the like are used. The amounts of these curing agents and curing accelerators used are, for example, epoxy resin 10
With respect to 0 parts by weight (hereinafter abbreviated as “part”), 3 to 30 parts of the above curing agent and 10 parts or less of the curing accelerator are used.

Next, the organic foaming agent (component B) is
It is added to the resin composition in order to impart heat-foamability. Examples of the organic foaming agent include azo compounds such as azodicarbonamide and azobisisobutyronitrile, nitroso compounds such as dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazide, 4,4 '.
And hydrazide compounds such as oxybenzenesulfonyl hydrazide. These organic foaming agents can be used alone or in combination of two or more kinds.
Among them, those having a decomposition and foaming temperature of 80 ° C. or higher are preferable from the viewpoint of the storage stability and stability of the thermosetting foamable resin composition. Further, the compounding amount of the organic foaming agent is 2 to 12 parts with respect to 100 parts of the thermosetting resin (component A),
It is preferably 3 to 10 parts, and particularly preferably 4 to 8 parts. If the blending amount of the foaming agent is less than 2 parts, it may not be possible to reduce the weight of the cured resin composition due to foaming, and conversely if the blending amount exceeds 12 parts, the cured resin composition obtained is This is because there is a tendency that the foaming becomes excessive and the reinforcing property decreases.

A foaming aid may be used in combination with the above organic foaming agent (component B). Examples of the foaming aid include inorganic foaming aids such as zinc white, metal soaps such as zinc stearate, and urea compounds.

As described above, the thixotropy-imparting agent (component C) is usually a putty-like or sheet-like thermosetting foamable resin composition, which is dripping during application or a sheet during application. It is added in order to prevent deviation and peeling. Further, by adding the thixotropic agent, the foamed cells of the resin composition after curing and foaming become minute and uniform, so that the structural strength is improved, and the properties such as soundproofing, vibration damping, and heat insulation are excellent. The advantage is that Examples of the thixotropic agent include aerosil, asbestos fiber, and organic bentonite. Of these, organic bennatonite is most suitable. That is, among the above thixotropy-imparting agents, the organic bentonite is most excellent in imparting thixotropy and the uniformity and minuteness of the foamable cells. As the above-mentioned organic bentonite, one having an average particle diameter of 1 to 5 μm is usually used.

The mixing ratio of the thixotropy-imparting agent is generally in the range of 5 to 20 parts, preferably in the range of 5 to 15 parts, and most preferably 8 parts, relative to 100 parts of the thermosetting resin (component A).
It is in the range of 13 parts. That is, when the mixing ratio of the thixotropic agent is less than 5 parts, the thixotropy imparting to the resin composition becomes insufficient, and when the resin composition is applied, dripping or sheet misalignment, after curing This is because there is a possibility that peeling of the material will occur. On the contrary, the mixing ratio of the thixotropic agent,
If it exceeds 20 parts, the resin composition after curing will be insufficiently foamed, and desired properties such as improvement in structural strength, soundproofing property, heat insulating property and vibration insulating property may not be obtained.

Next, the fine hollow particles (component D) used in the present invention will be described. Examples of the fine hollow particles include inorganic ones such as alumina silicate, glass and silica, and organic ones such as phenol, vinylidene chloride, vinylidene chloride-acrylonitrile copolymer and melamine resin. Among these, from the viewpoints of rigidity and density, alumina silicate, vinylidene chloride type and the like are preferable, and alumina silicate is most preferable. Further, the particle size of the fine hollow particles is generally 5 to 300 μm.
m, optimally in the range of 30 to 150 μm. The density of the fine hollow particles is preferably from 0.8 g / cm ³ or less, and optimally, a range of 0.04~0.7g / cm ^3. The shape of the fine hollow particles is not particularly limited, but is preferably spherical.

One of the purposes of blending the fine hollow particles (component D) is to adjust the density of the resin composition before curing. That is, when the thixotropy-imparting agent is blended in the above-mentioned predetermined ratio, it becomes possible to achieve both the impartation of thixotropy and the foamability. However, for example, under severe conditions such as the case where the surface to be coated is in an upright state and the width of the void is 20 to 30 mm, even when the thixotropy-imparting agent is blended in the above ratio, the thixotropic property-imparting agent may be mixed in Dripping, sheet misalignment, peeling, etc. occur. Therefore, in the present invention, the thixotropy imparting agent is blended and the density of the resin composition is 1.0
By specifying g / cm ³ or less, the problems such as dripping or peeling can be solved. From such a point of view, the mixing ratio of the fine hollow particles is such that the density of the resin composition before curing is 1.0 g / cm ³ or less, and preferably,
0.9 g / cm ³ or less, optimally 0.5 to 0.8 g /
It is set to be cm ³ .

The density of the resin composition before curing is
The values are measured and calculated as follows. That is, a sample resin composition is prepared by kneading a mixture prepared by mixing components A to D, which are compounding components of the resin composition, and other additives in a predetermined ratio in a mixing pot while vacuum defoaming. . Then, in accordance with JIS K 6830, this is an item among them [5. Specific Gravity] The aluminum frame plate 10 (see FIG. 4) shown in FIG. 1 is prepared. A water mass of the aluminum frame plate _{10 (g) (W 1)} , to measure the mass of air in the aluminum frame plate 10 (g) (W _2), respectively. Then, first, the sample is filled in the groove 10a of the aluminum frame plate 10 for measuring the specific gravity so that air does not enter. Then, the mass of the aluminum frame plate 10 filled with the sample in the air by a chemical balance [W ₄ : aluminum frame plate 10
And the mass (g) of the sample in the air] are weighed, and then immersed in methanol and taken out quickly. Immediately after this, the mass in distilled water at 20 ± 2 ° C. [W ₃ : mass of aluminum frame plate 10 and sample in water (g)] was measured, and the above W
JIS K 6830 [5 using the values of ₁ to _W-4. specific gravity〕
Specific gravity D according to the formula described in (2) of Item 5.3
To calculate. The value (specific gravity D) thus measured and calculated is the density of the resin composition before curing.

Further, the addition of the fine hollow particles (component D) is effective not only for preventing the resin composition from dripping but also for forming fine cells. That is, even with these minute hollow particles, uniform minute cells are formed in the resin composition after curing and foaming, and the effect of improving the structural strength of hollow parts and the like, excellent soundproofing, vibration damping, heat insulating properties, etc. can be obtained. You can

The means for adjusting the density of the thermosetting expandable resin composition is not limited to the above-mentioned adjustment by the fine hollow particles (component D), but also the kind of each main component such as the thermosetting resin and the foaming agent. It can also be adjusted by selection. However, from the viewpoint of ease of adjustment, adjustment using the above-mentioned fine hollow particles (component D) is preferable.

Next, the thermosetting foamable resin composition of the present invention is produced, for example, as follows, using the components A to D. That is, the thermosetting resin (component A) is melted and mixed by a mixer such as a heating mixer. Then, in the melt-mixed thermosetting resin (component A), an organic foaming agent (component B), a thixotropic agent (component C), fine hollow particles (component D), and, if necessary, a curing accelerator An additive such as a foaming aid or the like is blended in a predetermined ratio. And
A putty-like thermosetting foamable resin composition can be produced by kneading this mixture using a mixing roll or the like. Further, the putty-like thermosetting foamable resin composition is subjected to hot press molding through a release paper at a temperature not higher than the decomposition temperature of the foaming agent to obtain a sheet-like thermosetting foamable resin composition. You can The thickness of the sheet-shaped thermosetting foamable resin composition is generally 2 to 15 m.
m, preferably 3 to 10 mm.

The putty-like or sheet-like thermosetting foamable resin composition thus obtained is used as follows. That is, in the case of a putty shape, it is applied by a spatula method or the like, or when it is formed into a sheet shape, it is adhered to the voids and the like of parts made of a thin plate member such as an automobile door. At this time, a thixotropic agent (component C)
And since the density of the resin composition is specified,
Even if the surface to be coated or adhered is a standing thin plate member or the inner peripheral surface of the pipe, dripping, deviation of the sheet, peeling, etc. do not occur. And a predetermined temperature (usually 80 ℃ or more)
When heated to, the resin composition is cured and expanded by the curing by the thermosetting resin (component A) contained and the foaming by the organic foaming agent (component B), and the voids are filled without any gap. Will be done. In this way
It is possible to improve the structural strength of hollow parts such as automobile doors and various pipes, and to impart excellent properties such as soundproofing, vibration damping, and heat insulating properties.

[0026]

As described above, the thermosetting foamable resin composition of the present invention has a density of the resin composition before curing set to a specific value or less, and a thixotropy-imparting agent, an organic foaming agent, and micro hollows. By incorporating the particles, problems such as dripping during coating or sheet misalignment during sticking are solved without impairing foamability. Therefore, the thermosetting foamable resin composition of the present invention is used in an upright state for 20 to 30 minutes.
When it is used as a reinforcing material for hollow parts or various pipes having voids with a width of mm or more, it becomes possible to adhere or evenly coat the voids without causing a sheet shift or the like. When the coated or adhered thermosetting foamable resin composition of the present invention is heated, it is sufficiently cured and foams and expands, so that the voids of the hollow parts can be filled without any gap. As described above, the thermosetting foamable resin composition of the present invention has excellent curability and foam expansion properties, and is not limited to the object to be coated or attached. Therefore, if the thermosetting foamable resin composition of the present invention is used as a reinforcing material for automobile doors, for example,
By simple coating and pasting work, the structural strength is significantly improved without compromising the weight reduction of the door, and excellent soundproofing,
It is possible to add properties such as vibration isolation and heat insulation.

Next, examples will be described together with comparative examples.

[0028]

Example 1 As thermosetting resin (component A), 60 parts of bisphenol A type liquid epoxy resin (Epicoat # 828, manufactured by Yuka Shell Co., Ltd.) and bisphenol A type solid epoxy resin (Epicoat # 1002, oilified shell). 4)
0 parts were prepared, and these were melt-mixed in a mixing pot. Then, with respect to 100 parts of this molten mixture (component A), 5 parts of a hydrazide-based foaming agent, 10 parts of organic bentonite (component C) (average particle diameter 3 μm), alumina silicate (component D) [density 0.6 to 0. 7 g / cm ³ ] 70 parts, dicyandiamide (hardener) 5 parts, imidazole-based hardener 0.
6 parts were blended, and these were kneaded using a mixing roll. Then, the obtained resin block was hot-pressed (condition: press temperature 60 ° C.) through release paper to obtain a sheet-shaped thermosetting foamable resin composition having a thickness of 4 mm.

[0029]

Examples 2 to 8 The materials shown in Table 1 below were mixed in the proportions shown in the same table, and sheet-like thermosetting foamable resin compositions were prepared in the same manner as in Example 1.

[0030]

[Table 1]

[0031]

[Comparative Examples 1 to 3] The sheet-like thermosetting foamable resin composition was prepared in the same manner as in Example 1, except that the materials shown in Table 2 below were mixed in the proportions shown in the same table. In Comparative Example 1, the fine hollow particles (D component) were not blended, and in Comparative Example 2, the thixotropy imparting agent (C component) was not blended. Further, in Comparative Example 3, the resin composition has a density of more than 1.0 g / cm ³ .

[0032]

[Table 2]

The densities of the respective resin compositions before curing shown in Tables 1 and 2 were measured and calculated according to JIS K 6830 according to the above-mentioned measuring method. Then, with respect to the example products 1 to 8 and the comparative example products 1 to 3 obtained in this way, a void filling test, a shift test and a rigidity test were performed, and their characteristics were examined. The results are shown in Table 3 below.
And shown in Table 4. The various tests described above were carried out by the following methods.

[Void Filling Test] Metal Square Pipe (25
mm × 25 mm × 150 mm height) and a sheet-like thermosetting foamable resin composition (25 mm × 100 mm × 4 mm thickness) were prepared. Then, as shown in FIGS. 1 (A) and 1 (B), the two sheet-shaped thermosetting foamable resin compositions 1 described above are used.
Was attached to the inner peripheral surface of the metal square pipe 2. Figure 1 (A)
Is a perspective view showing a pasted state, and FIG. 1 (B) is
It is the sectional view. In this state, the metal square pipe 2,
After heating in an oven at 170 ° C. for 20 minutes for heat treatment, it was taken out of the oven, and the foam filling state of the resin composition 1 inside the square metal pipe 2 was visually observed. And
Those that were completely filled were marked with ◯, and those that were insufficiently filled, that the resin had fallen off or were displaced, or those that had insufficient foam expansion were marked with x.

[Displacement Test] In the void filling test, the length of displacement between the tip of the adhered sheet-shaped thermosetting foamable resin composition and the tip of the metal square pipe after heat foaming was measured. . The deviation length of 5 mm or less is indicated by O, the deviation length of 6 to 10 mm is indicated by Δ, and the deviation length of 10 mm or more is indicated by X.

[Rigidity Test] As shown in FIG. 2A, the test steel plates 3a and 3b (25 mm × 150 mm × 0.8 mm)
(Thickness) is prepared, and a sheet-shaped thermosetting foamable resin composition (25 mm × 120 mm × 4 mm) is provided on one of the test steel plates 3 b.
(Thickness) was attached. Then, as shown in the drawing, another test steel plate 3a was placed on the above-mentioned adhered sheet-shaped thermosetting foamable resin composition via the spacer 4 (height: 12 mm). In this state, the test steel plates 3a and 3b and the sheet-shaped thermosetting foamable resin composition 1 were placed in an oven at 170 ° C. for 20 minutes.
2 minutes, it heat-processed, as shown in FIG.2 (B), the sheet-shaped thermosetting foaming resin composition was foam-expanded, and this was made into the test piece of a rigidity test. A bending test was performed on this test piece as shown in FIG. That is, as shown in the figure, the test piece is placed on the two support bases 5a and 5b, and in this state, the rod-shaped member is lowered (bending speed: 5 mm / min).
Then, the bending strength was measured. In the figure, L is a distance (span distance) of the support bases 5a and 5b of 100 mm.

[0037]

[Table 3]

[0038]

[Table 4]

From Table 3 above, the sheet-like thermosetting foamable resin compositions of all the examples contained the thixotropy-imparting agent, and the density of the resin composition was set to 1.0 g / cm ³ or less. As a result, the heat treatment caused sufficient foaming, and the sheet did not slip or fall off. The sheet-shaped thermosetting foamable resin compositions of all the examples were also excellent in rigidity. On the other hand, in Comparative Examples 1 and 3, the density of the resin composition exceeds 1.0 g / cm ³ , so that the foaming is insufficient, the void filling property and the slippage property are poor, and the rigidity is low. It was Further, in Comparative Example 2, since the thixotropy-imparting agent is not blended, the sheet-shaped resin composition falls off in the porosity test, and the resin composition also flows in the rigidity test, so that the test can be performed. There wasn't.

[Brief description of drawings]

FIG. 1A is a perspective view showing a state in which a sheet-shaped thermosetting foamable resin composition is attached to the inner peripheral surface of a metal square pipe in a void filling test, and FIG. It is the sectional view.

FIG. 2A is a cross-sectional view showing a state before heat treatment of a test steel plate and a sheet-shaped thermosetting foamable resin composition in a rigidity test, and FIG. 2B shows a state after heat treatment. It is sectional drawing shown.

FIG. 3 is a configuration diagram showing a state in which bending strength is measured in a rigidity test.

FIG. 4 is a perspective view showing an aluminum frame plate for measuring specific gravity used when measuring the density of a resin composition before curing.

Claims (3)

[Claims] 1. A thermosetting foamable resin composition comprising the following components (A) to (D) and having a resin composition density of 1.0 g / cm ³ or less. . (A) Thermosetting resin. (B) Organic foaming agent. (C) A thixotropic agent. (D) Micro hollow particles. 2. The thermosetting foamable resin composition according to claim 1, wherein the thixotropy-imparting agent as the component (C) is organic bentonite. 3. The thermosetting foamable resin composition according to claim 1, wherein the fine hollow particles of the component (D) have a density of 0.9 g / cm ³ or less.