JPS6326693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a composite resin foam, and more specifically, the present invention relates to a method for producing a composite resin foam, and more particularly, the present invention relates to a method for producing a composite resin foam, and more specifically, a flexible porous body having open-celled cells, in which a resin foam such as polyurethane foam or polyester foam is added to the open-celled cells. The body has a uniform density throughout the structure with even distribution;
The present invention also relates to a method for producing a composite resin foam having small anisotropy.

In order to obtain resin foam such as polyurethane foam, the conventional method has been to discharge a certain amount of the resin foam stock solution into a container such as a wooden box without a lid, and allow the resin foam to foam and harden freely within the container. ing. Of course, if necessary, there is also a method of continuously obtaining resin foam by discharging the stock solution onto a belt conveyor running at a constant speed and allowing it to foam and harden freely on the belt conveyor. . However, in any case, since the resin foam obtained by these methods expands upward against gravity, it is unavoidable that density differences occur in the height direction, and generally, the resin foam obtained by these methods expands upwards against gravity, so it is inevitable that the density difference will occur in the height direction. There is a tendency for the foam density to decrease as one moves upward. In addition, there is a large difference in physical properties between the foaming direction and the direction perpendicular to it, and the anisotropy is large. Furthermore, in general, when foaming is performed in a closed mold called molding, a foam with a high density at the periphery and a low density at the center is obtained, and a foam with uniform density cannot be obtained. . In order to improve these drawbacks, a method has been devised and partially implemented in which the foam is gradually foamed while pressurizing the upper end of the foam with a restraining plate from the beginning or during the foaming process to obtain a foam with as small a difference in density in the vertical direction as possible. However, satisfactory results have not always been obtained.

Therefore, the present inventors conducted extensive research with the aim of providing a resin foam that has uniform density throughout and has low anisotropy.
By compressing a flexible porous body with open cells to a certain extent, impregnating it with a resin foam stock solution in the compressed state, and then foaming and curing it under certain conditions, resin foaming that meets the above purpose can be achieved. The present invention was completed based on the discovery that the present invention can be obtained.

According to the present invention, a flexible porous body having open cells is compressed until its pore volume becomes substantially equal to the volume of the resin foam stock solution to be impregnated, and the compressed Substantially completely filling the voids of the porous body with the resin foam stock solution, and then
A method for producing a composite resin foam is provided, which comprises foaming and curing a porous body impregnated with the resin foam stock solution under pressure at a rate lower than its free foaming rate.

The present invention will be explained in more detail below.

In the method of the present invention, first, a flexible porous body having open cells is compressed until the pore volume thereof becomes substantially equal to the volume of the resin foam stock solution to be impregnated, and the compressed The voids in the porous body are substantially completely filled with the resin foam stock solution.

The "flexible porous material with open cells" used in this first step consists of an aggregate of many cells that communicate with each other, and the cell skeleton is made of a flexible material. , for example, is composed of a natural, recycled or synthetic polymeric material and can be compressed without substantially destroying its cell structure, specifically, for example, soft polyurethane foam, sponge rubber, etc. , sponge, viscose sponge, vinylon sponge, etc. Among them, the apparent specific gravity is generally 0.01 to 0.1, preferably
Those within the range of 0.01 to 0.05, especially flexible polyurethane foams, are preferred.

Generally, it is preferable to select and use such a porous body that has good affinity for the resin foam stock solution to be impregnated, and generally,
0.8, preferably 0.9 or more, more preferably 0.95
It is advantageous to have a porosity greater than or equal to the porosity. here,
"Porosity" refers to the ratio of the volume of the space communicating with the outside of the porous body to the total apparent volume of the porous body in question, and is a value that can be calculated using the following formula. .

Porosity = Volume of space communicating with the outside in a porous body/total apparent volume of the porous body According to the present invention, the above flexible porous body is compressed and A resin foam stock solution is impregnated so that the voids of the compressed porous body are substantially completely filled with the resin foam stock solution.

The degree of compression of the porous body varies depending on the porosity of the porous body, the density of the resin foam stock solution to be impregnated, the density required for the final product composite resin foam, etc. It is necessary to compress the porous body until the pore volume after compression becomes substantially equal to the volume of the resin foam stock solution to be impregnated.

The resin foam stock solution that can be impregnated includes those that are initially liquid and gradually react spontaneously and foam to form a hardened resin foam,
For example, prepolymers for producing polyester resin foams; liquid mixtures of polyisocyanate components and polyol components and supporting components such as catalysts and blowing agents for producing polyurethane resin foams; polyisocyanates for producing polyisocyanurate resin foams. Examples include liquid mixtures of components and supporting components such as catalysts and blowing agents, and if necessary, modifier components such as polyols and epoxy.Among them, polyurethane resin foam stock solutions and polyisocyanurate resin foam stock solutions include: It is suitable for the purpose of the present invention because the speed of foaming and expansion, expansion ratio, etc. can be freely changed over a wide range, and compositions with a viscosity range suitable for impregnation into porous materials can be easily obtained. The process of the invention is particularly suitable for producing uniform density rigid polyurethane foams and rigid polyisocyanurate foams.

Such a resin foam stock solution can be prepared by a method known per se, for example, "Polyurethane Resin" by Keiji Iwata (published by Nikkan Kogyo Shimbun), Bridgestone Tire Co., Ltd. Technical Headquarters and Nippon Trading Co., Ltd.
It can be carried out according to the conventional method described in literature such as "Polyurethane" (published by Maki Shoten) co-edited by Planning Department, but in the present invention, suitable polyurethane resin foam stock solution and polyisocyanurate resin foaming are used. The composition and preparation method of the body solution will be explained in more detail below.

(1) Polyurethane resin foam stock solution Prepared by mixing a polyisocyanate component and a polyol component with a blowing agent and a urethanization catalyst as essential components. As the polyisocyanate component, any polyisocyanate compound commonly used in the production of polyurethane can be used, for example,
Includes aliphatic, aromatic or aromatic-substituted aliphatic polyisocyanate compounds, specifically 4,4'-diphenylmethane diisocyanate and its alkyl homologs, 2,4- or 2,6 - toluylene diisocyanate and its isomer mixtures, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, m-xylylene diisocyanate, etc.; or homologs containing three or more isocyanate groups per molecule. Examples include crude toluylene polyisocyanate and crude diphenylmethane diisocyanate. Furthermore, a prepolymer having active isocyanate groups obtained by reacting an excess amount of a polyisocyanate compound as described above with a polyhydroxy compound; or a semi-prepolymer obtained by mixing such a prepolymer with a polyisocyanate compound as described above. Prepolymers can also be used.

On the other hand, for the polyol component, any polyol compound commonly used in the production of polyurethane can be used, such as linear or branched polyether polyols, polyester polyols, and polythioether polyols having two or more hydroxyl groups. , polyacetal polyols, and mixtures thereof, which generally have a hydroxyl equivalent in the range of 100 to 3,000 and the number of hydroxyl groups present in one molecule is in the range of 2 to 8 are suitable. As is well known, among such polyol compounds, those with a low number of functional groups give a soft polyurethane foam, while those with a high number of functional groups give a hard polyurethane foam. In addition to the above, polyol components include vinyl compounds and diene compounds (e.g., polystyrene, polyacrylonitrile, polyvinyl chloride, polybutadiene) substituted with a hydroxyl group at the end, as well as ethylene glycol, propylene glycol, butanediol, Low molecular weight polyols, commonly referred to as crosslinking agents, such as glycerin, can also be used.

A polyurethane foam stock solution can be prepared by simply adding a blowing agent and a urethanization catalyst to the polyisocyanate component and polyol component described above and mixing them. This mixing can be done by, for example, mixing each component weighed in a container by hand with a stirring rod or by using power such as an electric drill.Furthermore, it is usually possible to use a mechanized device called a foaming machine for measuring and mixing the stock solution. It can also be carried out using a device etc. In general, the mixing ratio of the polyisocyanate component and the polyol component during this mixing is such that the polyisocyanate component is based on the total amount of active hydrogen atoms in the polyol component present in the mixed stock solution and other active hydrogen compounds mixed as necessary. The proportions may be such that it is present in at least the required stoichiometric amount.

Examples of the blowing agent used in the polyurethane foam stock solution include water, low-boiling hydrocarbons (e.g., butane, pentane, hexane, etc.), and low-boiling halogenated hydrocarbons (e.g., methylene chloride, monochlorodifluoromethane, trichloromonofluoromethane, etc.). Dichlorodifluoromethane, dichlorotetrafluoroethane, trichlorotrifluoroethane, etc.) are used alone or in combination, and as catalysts, for example, triethylenediamine, triethylamine, dimethylethanolamine, dimethylcyclohexylamine, tetramethylethylenediamine, dimethyl Tertiary amines such as benzylamine and morpholine; tin compounds such as stannous dilaurate are used.

Furthermore, the polyurethane foam stock solution contains
As usual, crosslinking agents, surfactants, flame retardants, and other additives can be included as desired. Examples of crosslinking agents include ethylene glycol, propylene glycol, propanediol, butanediol, hexanediol,
Dipropylene glycol, glycerin, etc. are used, and block copolymers of polydimethylsiloxane and alkylene oxide are mainly used as surfactants. Unicar),
YF8063 (Toshiba Silicon Company), F-305 (Shin-Etsu Chemical)
etc. Each of these components can be used in the amounts normally used, for example, the blowing agent is about 1.0 to 40% by weight based on the weight of the stock solution.
in the range of about 0.1 to about 5% by weight of the catalyst;
Crosslinkers can be used in a range of about 0.1 to about 10% by weight, and surfactants in a range of about 0.5 to about 2.0% by weight.

Furthermore, if necessary, other additives may be added to the polyurethane foam stock solution, such as flame retardants [e.g., halogenated phosphate esters, halogenated paraffins, antimony trichloride, etc.], antioxidants [e.g., UOP-38, UOP-288 (manufactured by Japan Gasoyu Co., Ltd.)], ultraviolet absorber [e.g. Irganox
1010 (manufactured by Geigy)], pigments (e.g. Carbon Black, Polyton Blue, Polyton Green (manufactured by Dainippon Ink)), and fillers to the extent that they do not impede the permeability of the stock solution into the porous layer [e.g. : wood flour,
Glass powder, glass microballoons, graphite, hydrated alumina], etc. may also be included.

(2) Polyisocyanurate resin foam stock solution Polyisocyanurate stock solution has the following composition:
The polyol component is omitted from the polyurethane foam stock solution, and an isocyanate trimerization catalyst is introduced as an essential component instead, and it is a type of resin stock solution that is cured mainly by forming isocyanurate bonds.

Thus, trimerization catalysts that can be used include, for example, alkali metal salts of aliphatic carboxylic acids (e.g. potassium octoate), alkali metal salts of aromatic carboxylic acids (e.g. potassium benzoate), strong organic bases [e.g. 2,4,6-tris-(dimethylaminomethyl)phenol, 2,4,6-tris-(diethylaminomethyl)phenol, N,N',N''-tris-(dimethylaminopropyl)-sym-hexahydrotriazine , benzyltrimethylammonium oxide, sodium methoxide], but are not limited to these, and other conventional trimerization catalysts can also be used.The amount of these trimerization catalysts used is limited to a narrow range. Generally, based on the weight of the stock solution, approximately
A range of 0.1 to about 10% by weight is preferred.

Furthermore, it is possible to improve the brittleness of the resulting polyisocyanurate foam by adding a polyol compound or an epoxy compound to the polyisocyanurate foam stock solution as necessary to generate urethane bonds. Examples of polyol compounds that can be used for this purpose include hydroxyl equivalents obtained by adding propylene oxide and, if necessary, a portion of ethylene oxide to glycerin to have a secondary or primary hydroxyl group at the end.
100-2000 trifunctional polyether polyol,
Polyether polyols with a hydroxyl equivalent of 100 to 150, which are mainly made by adding propylene oxide to sucrose, polyether polyols with a hydroxyl equivalent of 100 to 150, which are mainly made by adding propylene oxide to sorbitol, and propylene to aliphatic or aromatic amine compounds. Examples of the epoxy compound include 3- to 8-functional polyether polyols with oxide added and a hydroxyl equivalent of 70 to 1000, and examples of epoxy compounds include epichlorohydrin adducts of bisphenol A. The blending amount of these polyol compounds or epoxy compounds is preferably 5 to 30% based on the equivalent weight of the polyisocyanate used, but is not limited to this range.

In the above-mentioned polyurethane and polyisocyanurate resin foam stock solutions, the curing reaction generally proceeds gradually even at room temperature, depending on the types of reaction components, due to the mixing of the respective components of the stock solutions described above.

The time required for a substantial reaction to occur varies considerably depending on the type of stock solution components, ambient temperature, etc., and cannot be generalized, but it is preferably approximately 30 seconds to 5 minutes.

The resin foam stock solution as described above is impregnated into the porous body having open cells either before or after compression of the porous body. In short, it is sufficient that the voids in the compressed porous body are almost completely filled with the resin foam stock solution. This impregnation can be carried out by methods of a type known per se, for example by adding a resin foam stock solution to the porous body before compression and then compressing it to the desired degree of compression; A method of compressing a solid body in a suitable mold and then pressurizing a resin foam stock solution; compressing a porous body having open cells in a closed mold, and maintaining the inside of the mold at reduced pressure to form a resin foam. This can be carried out using a method such as injecting a stock solution. What is important at this time is that substantially all of the voids existing in the compressed porous body are replaced with the resin foam stock solution, and the compressed porous body is filled with the resin foam stock solution. The goal is to ensure that virtually no unused space remains. Here, the term "substantially" can be used to mean allowing unsubstituted voids to remain to a degree that does not pose a practical problem in the final composite resin foam, and usually, There is no practical problem even if 20% or less, preferably 10% or less of the total volume of the voids in the compressed porous body are not filled with the resin foam stock solution.

In addition, if the porous body used has poor wettability with the resin foam stock solution, the porous body may be subjected to preliminary treatment to increase its affinity with the resin foam stock solution, such as treatment with a surfactant or drying. Depending on the treatment, the porous material may be subjected to degreasing treatment using a solvent, etc.

Further, the resin foam stock solution described above needs to be completely liquid until the voids (spaces) existing in the compressed porous body are substantially completely filled with the resin foam stock solution. However, since impregnation of the porous body can be carried out in a very short time, there is almost no problem as long as a commonly used resin foam stock solution is used.

As mentioned above, the degree of compression of the porous material depends on the actual density of the porous material used, the density of the resin foam stock solution to be impregnated, the proportion of the porous material in the final composite resin foam, etc. However, a person skilled in the art can easily determine the required degree of compression of the porous body from the density of the porous body used and the resin foam stock solution impregnated therein. For example, the density of a flexible porous body with open cells is
d _g is the density of the resin foam stock solution to be impregnated, d _e is the density of the resin foam stock solution to be impregnated, and the ratio (weight fraction) of the porous material to the foam desired for the composite resin foam that is the final product.
If r _g is the porosity of the porous body after compression, v _g can be expressed by the following formula (2). In other words, r _g = (1-v _g )d _g /v _g d _e + (1-v _g )d _g ...(1), and by transforming this equation (1), (r _g +d _g /d _e - d _g ) (v _g + d _g ／d _e −d _g )=d _g・d _e ／(d _e
−d _g ) ² …(2).

Therefore, as an example, the real density d _g is 1.07 g/cm ³
Taking as ^an example the case where a porous body consisting of a soft polyurethane _{foam of} +1.07/0.13) (v _g +1.07/0.13) = 1.28/0.
13 ² …(3). If this equation (3) is drawn on rectangular coordinates with v _g as the vertical axis and r _g as the horizontal axis, its locus becomes part of a hyperbola as shown in the attached Figure 1.

Therefore, if we are trying to manufacture a composite resin foam with a soft polyurethane foam content r _g of 0.2 as a final product, from Figure 1 we can see that the soft polyurethane foam will have a porosity (v _g ) of 0.78. It turns out that it has to be compressed.

Generally, the apparent density of flexible polyurethane foam is
Since it is 0.012 to 0.030 and the actual density is approximately 1.1, the porosity is in the range of 0.989 to 0.972. Therefore, it is clear that a flexible polyurethane foam with open cells is a porous material that can be used satisfactorily in the above example.

In addition, in this specification, the expression "a flexible porous body having open cells is compressed until the volume of its voids becomes substantially equal to the volume of the resin foam stock solution to be impregnated" , when the porous body has elasticity and can expand following the foaming expansion of the impregnated resin foam stock solution, the porosity of the porous body having open cells and after compression It closely matches the porosity desired for the porous body,
Please understand that this term is used to include exceptional cases where no compression operation is required.

The porous body having open cells used in the method of the present invention generally has a porosity of
A value of 0.5 to 0.95, preferably 0.6 to 0.9 is suitable.

The porous body impregnated with the resin foam stock solution as described above is then foamed, expanded and hardened under pressure at a rate less than its free foaming rate. Here, "free foaming speed" refers to the rate at which foaming and expanding resin is expanded with almost no external pressure applied, such as when foaming freely in a container or bag with a large opening under normal pressure. refers to the foaming speed when
In the present invention, the impregnated porous body is foamed and expanded while applying a load so that the foaming speed is lower than the free foaming speed. This results in
As the impregnated resin foam stock solution foams and expands, the compressed porous body also expands, creating a composite resin foam product in which the foamed and hardened resin is uniformly dispersed within the porous open cells. can get.

Foaming, expanding and curing of the resin foam stock solution can usually be carried out at room temperature, or may be carried out with heating if necessary, but the foaming, expanding and curing itself can be carried out by a conventional method. , there is no need to pay any special consideration.

The pressure applied to the impregnated porous body during foaming expansion and curing varies depending on the type of porous body and/or resin foam used and the desired expansion ratio of the final product, but in general, It is possible to vary the elastic recovery force over a wide range within a range of greater than the elastic recovery force of the resin foam and smaller than the expansion force of the resin foam stock solution, thereby making it possible to appropriately control the density and/or expansion ratio of the final product foam. In particular, in the present invention, when it is desired to obtain a composite with a relatively low density using a porous body with a small elastic recovery force, 10 g/
A slight pressure of about cm ² is sufficient; conversely, if you want to obtain a high-density composite by using a porous material with a large elastic recovery force or using a resin stock solution with a large free expansion ratio, There are cases where it is necessary to apply a pressure of ~3Kg/ ^cm2 , but in any case, lower pressure is preferable from the viewpoint of workability, and usually by selecting a resin stock solution with an expansion ratio that suits the purpose.
It is preferable to suppress it to 0.5Kg/cm ² or less.

Moreover, the pressure applied to the impregnated porous body is
The pressure may be held constant during foaming expansion, or the pressure may be adjusted so that the expansion rate is approximately constant.

Foaming and expansion of the porous body impregnated with the resin foam stock solution includes stopping gas generation of the resin foam stock solution components;
The process ends when the temperature rise stops, but if you want to stop the expansion at a preset expansion rate depending on the density and expansion ratio desired for the final product, you can stop the foaming expansion by mechanically restraining it. You can do it like this. This makes it possible to obtain a foam product with high dimensional accuracy.

The resin foam foamed and expanded in this way can then be aged at room temperature or under heating to complete curing, if necessary.

A composite resin foam product according to the invention can thus be obtained. According to the method of the present invention, the density of the composite resin foam product can be adjusted by appropriately adjusting the expansion ratio of the resin foam stock solution and the total expansion ratio of the composite resin foam, so that the density of the porous material to be impregnated can be adjusted. It can be freely changed as desired within a certain range.

For example, if the foaming ratio of the resin foam stock solution is E _f ,
By setting the apparent density of the composite resin foam of the final product to d _t , the total expansion ratio E _t of the final product can be calculated using the following formula (4).
It is expressed as

Note that the foaming ratio E _f and the total foaming ratio E _t have the following meanings.

E _f = Apparent volume of resin only after foaming/Volume of resin stock solution E _t = Apparent volume of composite resin foam/Total volume of resin foam and porous body when compressed before foaming E _t = v _g・d _e +(1−v _g )d _g /d _t …(4) From equation (4) and the above equation (2), E _t =d _g・d _e /d _t {(1−r _g ) d _g + r _g・d _e } …(5). Also, since E _t = v _g・E _f + (1−v _g ) …(6), from this equation (6) and the above equation (2), E _f = E _t + (E _t −1) r _g・d _e /(1−r _g )d _g …7 is derived.

Therefore, as in the above-mentioned specific example, a case is considered in which a porous body made of a flexible polyurethane foam with an effective density d _g of 1.07 g/cm ³ and a rigid polyurethane resin foam with a density d _e of 1.2 g/cm ³ are used. As usual, by substituting these values into the above equation (5), E _t = 1.07×1.2/d _t {1.07(1−r _g )+1.2r _g } = 1.28/d _t (1.07+0.13r _g ...(8) The relationship between E _t and r _g can be illustrated as part of a hyperbola as shown in the attached Figure 2.

Furthermore, by substituting the above numerical values into equation (7), E _f = E _t + 1.2 (E _t -1) r _g / 1.07 (1 - r _g ) = E _t + (E _t -1) 1.2 r _g /1.07(1-r _g )...(9) The relationship between E _f and E _t can be expressed by a straight line as shown in the attached Figure 3.

Thus, the flexible polyurethane foam content (r _g ) is 0.2 and the apparent density (d _t ) is 0.15 g/cm ³
If a composite polyurethane resin foam of In order to achieve a foam product density of 0.15 g/cm ³ , it is necessary to adjust the foaming expansion mentioned above so that the total foaming ratio of the final foam product is 7.8 times. From the figure, it is necessary to use a polyurethane resin foam stock solution with a free expansion ratio of at least 7.9 times.

Generally, the foaming ratio of the resin foam stock solution is about 3 to about
40, the total expansion ratio of the resulting composite resin foam can be in the range of about 2 to about 30 times, and thereby the apparent density can be approximately 0.05 to 0.5 g/cm. A composite resin foam within the range of ³ is obtained.

Furthermore, according to the method of the present invention, composite resin foams with a very low porous content to composite resin foams with a very high porous content can be manufactured as desired. However, it is generally preferred to have a porous content of from about 5 to about 200%, preferably from about 10 to about 50% by weight, based on the weight of the resin foam.

Next, the method of the present invention will be described with reference to FIGS. 4 and 5 of the accompanying drawings.
Further explanation will be given based on the embodiment shown in the figures.

FIG. 4 shows an embodiment in which the method of the present invention is carried out in batches. First, as shown in FIG. The flexible porous body 2 is leveled and placed so as to be uniformly dispersed. Next, as shown in FIG. 4B, a predetermined amount of the resin foam stock solution 3 is sprinkled onto the surface of the porous body 2 so as to spread it as evenly as possible, and the porous body 2 is immediately fitted into the opening of the mold 1. The matching lid 4 is fitted, a load P is applied to the lid 4, and the pore volume of the porous body 2 is added to the resin foam stock solution 3.
compress it until it becomes almost the same volume as [Figure 4C],
The voids in the porous body 2 are almost completely filled with the resin foam stock solution. Next, when the load P is reduced, the resin foam stock solution starts foaming and expanding, and the porous body also expands accordingly. When a predetermined total expansion ratio is reached, the expansion is stopped (FIG. 4D), and in this state, the product is cured and aged.

Alternatively, as shown in FIG. 4A, the porous body 2 is placed in the bottom of the concave mold 1 so as to be evenly distributed.
Next, a lid 4 is fitted into the mold 1, and the lid 4 is pressurized P to compress the porous body 2 to a predetermined porosity (FIG. 4B'). Thereafter, the resin foam stock solution 3 is forced into the hole provided at the bottom of the recess 1 to substantially completely fill the voids in the porous body 2 [Fig. 4 C'], and the pressure P is weakened to form the resin foam. Foaming and expanding the body solution 3,
Then, it is cured and aged (Fig. 4D).

As a result, a composite resin foam is obtained, which is a resin foam that is uniformly foamed and cured within the open cells of a flexible porous body having open cells.

FIG. 5 illustrates an embodiment in which the method of the present invention is carried out continuously, and shows a belt conveyor 1.
First, a sheet 11 that can serve as the lower surface of the composite resin foam is supplied from a roll 12 onto the sheet 11, and then a mat-like porous body 14 is fed onto the sheet 11 by a flexible porous body conveyor 13 having open air cells. Then, a resin foam stock solution 16 is sprinkled onto the layer of the porous body 14 from a resin foam stock solution nozzle 15. Thereafter, a sheet 17 that can become the upper surface of the resin foam is supplied from the roll 18 to form the porous body 14.
are sandwiched in a sandwich-like manner, and the layer of the porous body 14 sprinkled with the resin foam stock solution 16 is further compressed by the compression roller 19, so that the sprinkled resin foam stock solution fills the voids of the porous body. Ensure that the requirements are met almost completely without excess or deficiency. Next, the porous body impregnated with the resin foam stock solution is passed between the belt conveyor 10 and the upper conveyor 20, where it foams, expands, and hardens until it reaches a predetermined thickness. At step 22, it is cut to a predetermined length. Thereby, the composite resin foam according to the present invention can be manufactured continuously.

A suitable surface material can be attached to at least one surface of the foam obtained by the present invention. At this time, in the batch type described above, the surface material can be provided by placing the surface material in the mold in advance, and in the continuous type, the sheets 11 and 17 serve as the surface material. As the surface material, any material such as cellulose paper, glass paper, metal plate, plastic film, etc. can be used.This enhances the beauty of the composite resin foam, and further improves the strength of the product due to the sandwich structure effect. Obtainable.

Furthermore, the flexible porous body used in the present invention is
Although the composite resin foam itself may serve as a reinforcing material, it can be reinforced with a reinforcing material other than the porous material. Reinforcing materials for this purpose include porous sheet-like materials with relatively high mechanical strength through which the aforementioned resin foam stock solution can easily penetrate or permeate, such as wire mesh, glass mesh, and honeycomb structures (made of metal, paper, or plastic). body, nature,
Examples include non-woven fabrics and knitted fabrics made of recycled or synthetic fibers. These reinforcing materials can be incorporated into the skin of the composite resin foam of the final product by superimposing them on one or both sides of the porous body prior to impregnation of the resin foam stock solution into the porous body. [See Examples 2, 3 and 4 below].

Alternatively, in the present invention, the porous body has 2
It is also possible to use more than one porous material in combination [therefore, the term "porous material" as used herein includes a laminate of two or more such porous materials], At that time, by laminating the reinforcing material on at least one overlapping surface of the two or more porous bodies, a reinforced composite resin foam product having a reinforcing material layer inside the foam can be obtained. .

As described above, according to the method of the present invention, a composite resin foam having a uniform density, low anisotropy, and appropriately reinforced as required can be obtained. In particular, depending on the combination of the porous material layer and the reinforcing material, it is possible to insert the reinforcing material not only in the surface layer but also at any arbitrary position within the foam.

Therefore, the composite resin foam of uniform density and suitably reinforced provided by the present invention can be effectively used as, for example, a heat insulating material or a strength member. That is, in the case of resin foams obtained by conventional methods, the density difference and anisotropy are large, so when considering the minimum value of physical properties, the overall density is high,
In many other areas, it was necessary to use products of excessive quality, but the composite resin foam provided by the method of the present invention has a performance that is most suitable for its intended use when manufactured. Since it can be freely adjusted, there are various advantages such as being able to reduce the weight, use weight, and cost reduction.

Next, the present invention will be further explained with reference to Examples.

Example 1 Inside a concave metal mold with an inner area of 200 x 200 mm and a depth of 150 mm, a mold with a size of 200 x 200 mm, a thickness of 130 mm, and a weight
130g of open-celled soft polyurethane foam mat [manufactured by Nisshinbo Co., Ltd.: Peach urethane D-]
25: apparent specific gravity 0.025, real specific gravity 1.07]. Next, on this soft polyurethane foam mat,
Quickly pour 1000g of a hard polyurethane foam stock solution with the following properties obtained by mixing liquids A and B2 with the following composition, place a metal plate with a weight of 5kg that is large enough to fit into the concave mold, and place it in the press. A pressure of 1 ton (2.5 kg/cm ² ) was applied to the entire surface of the metal plate to compress the contents.

Composition: <Liquid A> Polyol [manufactured by Sanyo Chemical Co., Ltd.; HR-450P]
30.7 parts by weight polyol [manufactured by Asahi Denka Kogyo Co., Ltd.; Quadrol]
5.0 〃 Triethyldiamine 0.06 〃 Water 0.2 〃 Foam stabilizer [manufactured by Toray Silicon Co., Ltd.; SH-193]
1.0 〃 Freon-11 10.0 〃 <Liquid B> Crude diphenylmethane diisocyanate [manufactured by Sumitomo Bayer Urethane Co., Ltd.; 44V-20] 53.0 〃 Reaction rate and foaming ratio of rigid polyurethane foam stock solution (20℃): Cream time: 50 seconds Rise time: 4 minutes Stock solution specific gravity: 1.2 g/cm ³ Free expansion ratio: 30 times The time required from pouring the stock solution to completion of compression was approximately 15 seconds. Due to this compression, the hard polyurethane foam stock solution permeated into the soft polyurethane foam, and at the same time, the air inside the mold was pushed out through the gap between the fitting parts, and the final thickness of the soft polyurethane foam was approximately 25 mm. Next, the press is immediately opened, the pressure applied to the metal plate is removed, and the soft polyurethane foam is held under the pressure of only the load of the metal plate (12.5 g/cm ² ), and the soft polyurethane foam gradually lifts the metal plate. foamed and expanded. Approximately 30 minutes after starting inflation
The thickness reached 130mm after seconds. At this point, the metal plate was fixed and left at room temperature for 30 minutes. After 30 minutes, the composite rigid polyurethane foam was removed from the mold. This product had a uniform appearance and no defects such as pores were observed. Dimensions are 2200 x 200 x
The length was 130mm and the total weight was 1105g. Since the weight of the soft polyurethane foam used was 130 g, it was found that the weight of the impregnated hard polyurethane foam stock solution was 975 g. The injection amount of hard polyurethane foam stock solution is 1000g, so the difference is 25
It is thought that g corresponds to the loss caused by burrs from the fitting portion of the metal plate.

Since the composite obtained in this example was manufactured from 130 g of soft polyurethane foam (actual specific gravity = 1.07) and 975 g of hard polyurethane foam (specific gravity of stock solution = 1.2), the stock solution completely filled the voids in the soft polyurethane foam during compression. Assuming that the volume is 934 cm ³ as calculated below,
becomes.

130/1.07+975/1.2=394 ( ^cm3 ) If this is put into a 20cm x 20cm mold, the thickness will be
Although it is calculated to be 23 mm, it was actually compressed to about 25 mm, so it can be said that the undiluted solution almost completely filled the void.

After removing 5 mm each of the upper and lower skin from the soft polyurethane foam-impregnated hard polyurethane foam obtained in this example, it was divided into three equal parts with a thickness of about 40 mm and the specific gravity of the upper, middle, and lower parts was measured. Each
They were 0.157, 0.157, and 0.158, and a uniform product was obtained throughout with almost no difference in specific gravity between the top, middle, and bottom.

Comparative Example 1 Using the same mold as in Example 1, a hard polyurethane foam stock solution with the same composition as in Example 1 was prepared.
1200 g was quickly poured into the mold, the metal top lid was fixed at a height of 150 mm from the bottom of the mold, and the mixture was left at room temperature for 30 minutes. After 30 minutes, the rigid polyurethane foam was removed from the mold and its dimensions were 200×.
The size was 200 x 150 mm and the total weight was 1170 g. Example 1
After removing the upper and lower epidermis in the same manner as above, we divided it into three equal parts with a thickness of about 45 mm and measured the specific gravity of the upper, middle, and lower parts, which were 0.147, 0.141, and 0.144, respectively, with the upper part having a higher specific gravity. It was a non-uniform foam product with a low specific gravity in the center.

Example 2 At the bottom of the same mold used in Example 1, a 200×200 mm
Wire mesh (zinc coated tortoise shell wire mesh #22 x 16m/m) 1
A hard polyurethane foam impregnated with soft polyurethane foam was prepared in exactly the same manner as in Example 1, except that the same soft polyurethane foam mat used in Example 1 was laid on top of the mat. The obtained composite rigid polyurethane foam had an appearance in which a wire mesh was uniformly embedded in the lower skin portion, had a uniform specific gravity throughout, and had no defects such as large pores.

Example 3 200% on the top and bottom of the soft polyurethane foam mat
x200mm size glass mesh (manufactured by Kanebo Stephens; KS-5430 5m/m) each
The same operation as in Example 1 was repeated except for stacking the sheets. The obtained composite rigid polyurethane foam had a glass mesh uniformly embedded in the upper and lower skin parts, had no defects such as large pores, and had a uniform specific gravity throughout.

Example 4 The same operation as in Example 1 was repeated, except that a urethane-modified polyisocyanurate foam stock solution with the following composition and properties was used as the resin foam stock solution.
Furthermore, the curing conditions were changed as follows.

When the resulting composite was observed, it was found that the cytoskeleton of the soft polyurethane foam was uniformly dispersed in the modified isocyanurate foam, and was uniform throughout the composite except for the skin layer.

Composition and properties of urethane-modified polyisocyanurate foam stock solution Composition <Liquid A> 2,4,6-tris-(dimethylaminomethyl)
Phenol 3.0 Foam stabilizer (Toray Silicone SH-193) 1.0 Freon-11 10.0 Polyether polyol (Sanyo Chemical Co., Ltd. GP-
400) 16.0 <Liquid B> Crude diphenylmethane diisocyanate (Sumitomo Bayer Urethane 44V-20) 70.0 Reaction rate and foaming ratio (20℃) Cream time: 35 seconds Rise time: 3 minutes Stock solution specific gravity: 1.2 g/cm ³ freedom Expansion ratio: 30x Curing conditions After being left at room temperature for 30 minutes, the mold was heated at 100° C. for 1 hour with the mold closed. After that, I waited for it to naturally cool down to room temperature and then took out the contents.

Example 5 A porous body of the same size as Example 1 was placed in a concave metal mold with an inner area of 400 x 300 mm, a depth of 150 mm, and a stock solution injection port with a diameter of 7 mm at the center of the bottom.
A soft polyurethane foam mat (300 g) measuring 400 x 300 x 100 mm was placed. Next, on top of this, a piece with a thickness of 25 mm and a weight that fits exactly into this concave mold is placed.
Place the 20Kg metal plates to mate and
The foam was compressed using a ton press until the thickness was 10 mm. Next, the same polyurethane foam stock solution as in Example 1 was poured into a high-pressure foaming machine (KRAUSS MAFFEI PU-
160) under the following conditions.

Discharge rate: 18Kg/min Injection pressure: 5Kg/cm ³ Injection time: 4.0sec After press-fitting, the clamping force of the press is set to zero, and the soft polyurethane foam is placed under the load of the metal plate (16.6
g/cm ² ) and press free rise drag (150 g/cm ² )
It was kept only. The metal plate gradually expands,
The thickness of the contents reached 80 mm approximately 90 seconds after the start of expansion.
Here, pressure was applied to the press again to restrain the position of the metal plate. After 30 minutes, the press was opened and the composite polyurethane foam was taken out from the mold.

This product is similar to that obtained in Example 1,
It had a uniform appearance, the soft polyurethane foam was uniformly dispersed inside, and no defects such as pores were observed. The dimensions of this thing are 400
x300 x 80mm, and the total weight was 1350g. The total weight of the soft polyurethane foam used is 300g.
Therefore, it can be seen that the weight of the hard polyurethane resin alone is 1050 g. The time required to inject the hard polyurethane foam stock solution is 4.0 seconds, so if you calculate from the discharge amount, it means that 1200g was injected, but considering the foaming machine's delay in operation and losses such as burrs, almost the entire amount could not be injected. It is thought that

Therefore, porous material (soft polyurethane foam)
The content rate is 22.2%. Note that the actual injection amount was calculated using the above-mentioned relational expression. That is, since the total volume when compressed is 40 x 30 x 1.0 cm = 1200 cm ³ and the weight of the soft polyurethane foam is 300 g, the porosity is 1200 - 300 / 1.07 / 1200 = 0.766.

Therefore, the polyurethane foam stock solution is 1200×
This means that it is sufficient to inject 0.766×1.2≒1103g.
Converting this to the number of seconds for ejection is 1103/18000×60=3.68 seconds. However, in reality, there is a delay in the operation of the foaming machine, loss and burrs in the process to the injection port, so in consideration of these, the injection amount was set at 4.0 seconds in the above example.

[Brief explanation of the drawing]

Figure 1 is an example of a graph showing the relationship between the porosity of the porous body during compression and the porous content of the composite resin foam as the final product. This is an example of a graph showing the relationship between the total expansion ratio and the porous material content, and FIG. 3 is an example of a graph showing the relationship between the expansion ratio of the resin foam stock solution and the total expansion ratio of the composite resin foam as a final product. FIG. 4 is a process diagram when the method of the present invention is operated in a batch manner, and FIG. 5 is a diagram of the process in which the method of the present invention is omitted when the method is carried out continuously. In Fig. 4, 1...concave type, 2...porous body, 3...
...Resin foam stock solution, 4...Lid.

Claims (1)

[Claims] 1 A flexible porous body with open cells,
compressing the porous body until its void volume is substantially equal to the volume of the resin foam concentrate to be impregnated, substantially completely filling the voids of the compressed porous body with the resin foam concentrate, and then A method for producing a composite resin foam, which comprises foaming and curing a porous body impregnated with a foam stock solution under pressure at a rate lower than its free foaming rate.