JP2018199818A - Thermally-foamable material, semisolid matter, method for molding semisolid matter, and method for producing foam - Google Patents

Abstract

To provide a thermally-foamable material which enables foams 1 and 20 excellent in physical properties such as a strength to be stably produced without requiring a labor.SOLUTION: The thermally foamable material includes an epoxy resin, a low-temperature curing agent which starts a reaction with the epoxy resin at a first temperature in the range of 60-120°C, a foaming agent which starts thermal expansion at a second temperature in the range of 80-160°C, and a high-temperature curing agent which starts a reaction with the epoxy resin at a third temperature in the range of 120-180°C, the second temperature being higher than the first temperature, the third temperature being higher than the second temperature, and viscosity of the thermally foamable material at 23°C being 10-60 Pa s. The thermally foamable material is heated to the first temperature or higher and the second temperature or lower and is cooled, and thereby can be formed into a semisolid matter having a viscosity at 60°C of 200-800 Pa s. The semisolid matter is heated to the third temperature or higher, and thereby is formed into a foam and can be cured.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a thermally foamable material used for the production of a foam, a semisolid formed from the thermally foamable material, a method for molding the semisolid, and a foam using the semisolid. It relates to a manufacturing method.

  2. Description of the Related Art Conventionally, members that require a predetermined thickness and strength, such as desk tops and doors, have been formed from FRP (fiber reinforced plastic). However, since the fiber which comprises FRP is expensive, the problem that the manufacturing cost of a member became high had arisen. Therefore, in order to reduce the manufacturing cost, only the outer shell of the member is formed from FRP, and the range to be the core material inside the FRP is formed from an inexpensive foam.

  Conventionally, various methods for producing the above-described foam have been proposed. For example, Patent Document 1 discloses a method for producing a foam using a compound of an epoxy resin, a curing agent, a foaming agent, and a thickener. Is disclosed.

  In the method of Patent Document 1, a kneading step of kneading a compound of an epoxy resin, a curing agent, a foaming agent, and a thickener, and applying the kneaded compound to a release paper or the like in a film form forms a resin sheet. A sheet forming process, a thickening process for thickening the resin sheet, and a foam curing process for foaming and curing the thickened resin sheet are sequentially executed.

Japanese Patent Laying-Open No. 2015-101670

  In the method of Patent Document 1, heating is performed in all of the above kneading step, sheeting step, thickening step, and foam curing step, and as a result, the viscosity of the blend changes as shown in FIG. It is done. Hereinafter, the reason why heating must be performed in all the above steps by the method of Patent Document 1 will be described with reference to FIG.

  Patent Document 1 discloses the use of an acrylic ester compound or a methacrylic ester compound as a thickener. These ester compounds are powdery. For this reason, it is thought that the blend of the epoxy resin / curing agent / foaming agent / thickening agent is initially a solid or a high-viscosity liquid at room temperature and has a high viscosity. Therefore, the above-mentioned compound cannot be kneaded at normal temperature, and therefore, it is considered that the compound is heated in the kneading step to lower the viscosity of the compound to a viscosity range suitable for kneading (A in FIG. 11). ).

The heating in the kneading step (A in FIG. 11) is performed at a temperature lower than the foaming start temperature (the temperature at which the foaming agent starts to expand) and the curing start temperature (the temperature at which the epoxy resin and the curing agent start to react). Done. For this reason, the heating in the kneading step (A in FIG. 11) does not involve a chemical reaction between the curing agent and the epoxy resin, but merely activates the molecular motion and temporarily lowers the viscosity of the formulation. Therefore, after the kneading step, it is considered that the viscosity of the blend returns to the original value as the temperature of the blend returns to room temperature (B in FIG. 11). And since the viscosity of the compound which became the same as the initial value is not in the viscosity range suitable for coating and coating, heating (hot melt) is performed again in the next sheet forming step, and the viscosity of the compound Must be lowered to a viscosity range suitable for coating and coating (C in FIG. 11).

  In the sheet forming step, the compound is made into a resin sheet. The heating (C in FIG. 11) in this sheet forming step is also performed at a temperature lower than the foaming start temperature and the curing start temperature to cause a chemical reaction. It doesn't let you. For this reason, it is considered that the viscosity of the resin sheet returns to the initial value again as the temperature of the resin sheet returns to room temperature even after the sheet process (D in FIG. 11). And since the viscosity of the resin sheet that is equal to the initial value is not in the viscosity range suitable for foaming, heating is performed in the next thickening step, and the viscosity of the resin sheet is adjusted to the viscosity range suitable for foaming. It is thought that it has increased (E in FIG. 11).

  In the thickening step, the resin sheet is heated (E in FIG. 11) at or above the thickening start temperature (the temperature at which the thickener swells, dissolves, or reacts) and is below the foaming start temperature. For this reason, in the heating in the thickening step (E in FIG. 11), although the viscosity increase of the resin sheet due to dissolution of the thickener occurs, foaming does not occur. Therefore, in the next foam curing step, the resin sheet needs to be heated again to the foaming start temperature or higher to cause foaming (F in FIG. 11). And even after foaming occurs, it is considered that heating is continued in order to cure the resin sheet (G in FIG. 11).

  For the above reasons, in the method of Patent Document 1, heating is required in all of the kneading step, sheet forming step, thickening step, and foam curing step, and among these, the kneading step, sheet forming step, and thickening step are heated. In (A, C, E of FIG. 11), it is necessary to perform strict temperature management in which the heating temperature is lower than the foaming start temperature and the curing start temperature.

  Further, in the kneading step, it is very difficult to give a uniform thermal history to all the formulations stored in the container so as to have a viscosity suitable for kneading. Even if the heating in the kneading step (A in FIG. 11) is performed at a temperature lower than the curing start temperature, the epoxy resin and A chemical reaction with the curing agent occurs causing an increase in viscosity, resulting in non-uniform quality of the resulting foam.

  From the above, it can be considered that the method of Patent Document 1 requires a great deal of labor to produce a foam and lacks feasibility.

  The present invention has been made in view of the above-mentioned matters, and the purpose thereof is a thermally foamable material capable of obtaining a foam in which uniform size bubbles are evenly distributed without requiring labor, The object is to provide a semi-solid formed from a thermally foamable material, a method for forming the semi-solid, and a method for producing a foam using the semi-solid.

  To achieve the above object, the present invention includes the subject matter described in the following section.

Item 1. A thermally foamable material used to produce a foam,
Epoxy resin,
A low temperature curing agent that initiates reaction with the epoxy resin at a first temperature;
A blowing agent that initiates thermal expansion at a second temperature;
A high temperature curing agent that initiates reaction with the epoxy resin at a third temperature,
The first temperature is in the range of 60 to 120 ° C, the second temperature is in the range of 80 to 160 ° C, the third temperature is in the range of 120 to 180 ° C, and the second temperature Is higher than the first temperature, the third temperature is higher than the second temperature,
The thermally foamable material has a viscosity at 23 ° C. of 10 to 60 Pa · s,
The thermal foamable material is heated to the first temperature or higher and the second temperature or lower to cause a reaction between the low temperature curing agent and the epoxy resin, and then the thermal foamable material is cooled, The thermally foamable material can be a semi-solid material having a viscosity at 60 ° C. of 200 to 800 Pa · s,
Heating the semi-solid to the third temperature or higher causes thermal expansion of the foaming agent to make the semi-solid into a foam, and causes a reaction between the high-temperature curing agent and the epoxy resin. A thermally foamable material capable of curing the foam.

Item 2. The epoxy resin is formed by mixing one or more of bisphenol type epoxy resin, novolac type epoxy resin, glycidylamine type epoxy resin, naphthalene type epoxy resin,
The low-temperature curing material is either an amine adduct type curing agent or a microcapsule type curing agent,
The high-temperature curing agent is a novolak resin, amines, dicyandiamides, imidazoles, or acid anhydrides,
The foaming agent is a thermally expandable microcapsule encapsulating a volatile liquid in a thermoplastic polymer shell, or a chemical agent that generates nitrogen gas, carbon dioxide gas, carbon monoxide, ammonia gas, or hydrogen gas when decomposed by heating. Item 2. The thermally foamable material according to Item 1.

  Item 3. Item 3. The thermally foamable material according to Item 1 or 2, wherein the content of the foaming agent is 10 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin.

Item 4. The epoxy resin is liquid,
The foaming agent is particulate,
Item 4. The thermal foaming property according to any one of Items 1 to 3, wherein the low-temperature curing material and the high-temperature curing agent are liquid or solid and have a potential of not reacting with an epoxy resin at 18 ° C to 23 ° C. material.

Item 5. A semi-solid material formed from the thermally foamable material according to any one of Items 1 to 4 and used to produce a foam,
A semi-solid material having a viscosity at 60 ° C. of 200 to 800 Pa · s due to the reaction between the low-temperature curing agent and the epoxy resin.

  Item 6. Item 6. The semi-solid material according to Item 5, which has a sheet shape.

  Item 7. Item 6. The semisolid according to Item 5, which exhibits a granular shape.

Item 8. A method for forming the sheet-like semisolid according to Item 6,
A kneading step of kneading the thermally foamable material according to any one of Items 1 to 4,
The kneaded thermal foamable material is applied to the surface of the release sheet, and the release sheet coated with the thermal foamable material is heated in an atmosphere of the first temperature or higher and the second temperature or lower. Thus, the reaction between the low-temperature curing agent and the epoxy resin contained in the thermally foamable material is caused, and then the thermally foamable material is cooled, so that the thermally foamable material is heated to 60 ° C. A sheet forming step for forming a sheet-like semi-solid having a viscosity of 200 to 800 Pa · s;
And a peeling step of peeling the sheet-like semi-solid from the release sheet.

Item 9. A method for molding the granular semi-solid according to Item 7,
A kneading step of kneading the thermally foamable material according to any one of Items 1 to 4,
The kneaded thermal foamable material is applied to the surface of the release sheet, and the release sheet coated with the thermal foamable material is heated in an atmosphere of the first temperature or higher and the second temperature or lower. Thus, the reaction between the low-temperature curing agent and the epoxy resin contained in the thermally foamable material is caused, and then the thermally foamable material is cooled, so that the thermally foamable material is heated to 60 ° C. A sheet forming step for forming a sheet-like semi-solid having a viscosity of 200 to 800 Pa · s;
A peeling step of peeling the sheet-shaped semi-solid from the release sheet;
A molding method comprising: chopping the sheet-like semi-solid material, and forming a granular semi-solid material by making each of the chopped materials granular with a predetermined particle size.

  Item 10. In the application step, the release sheet moves below the blade, or the blade moves above the release sheet, so that the thermally foamable material applied to the surface of the release sheet Item 10. The molding method according to Item 8 or 9, wherein the surplus portion is scraped off by the blade.

Item 11. A method for producing a foam using the sheet-like semi-solid material according to Item 6,
A pasting step of pasting the semi-solid material on the surface of the plate;
The plate material on which the semi-solid material is pasted is put into the mold, and the interior of the mold is heated to the third temperature or higher, thereby causing thermal expansion of the foaming agent and foaming the semi-solid material. And a foam curing step of curing the foam by causing a reaction between the high-temperature curing agent contained in the foam and the epoxy resin.

Item 12. By combining a plate material (hereinafter referred to as an adhesive plate material) to which the semi-solid material is attached and another plate material, the internal space is surrounded by the adhesive plate material and the other plate material, and the wall surface of the internal space And further comprising an assembly step of assembling the box to which the semi-solid material is attached,
Item 12. The method for producing a foam according to Item 11, wherein, in the foam curing step, the box is put into a mold and the interior of the mold is heated to the third temperature or higher.

Item 13. Item 12. A method for producing a foam using a granular semi-solid according to Item 11,
A charging step of charging the semi-solid into a recess formed on the surface of the plate;
Heat of the foaming agent contained in the semi-solid is obtained by putting the plate material in which the semi-solid is put into the recess into the mold and heating the inside of the mold to the third temperature or higher. A foam-curing step of causing expansion of the semi-solid to form a foam, and a reaction between the high-temperature curing agent contained in the foam and the epoxy resin to cure the foam. , Method for producing foam.

  Item 14. Item 14. The method for producing a foam according to any one of Items 11 to 13, wherein the plate material is a carbon fiber prepreg.

  According to the present invention, it is possible to obtain a foam in which uniformly sized bubbles are evenly distributed without requiring labor.

It is sectional drawing which shows the foam manufactured from the thermally foamable material of embodiment of this invention. It is sectional drawing which shows the sheet-like semi-solid material which is shape | molded from the thermally foamable material of embodiment of this invention, and is used in order to manufacture a foam. It is a flowchart which shows the process of shape | molding a sheet-like semi-solid. It is a flowchart which shows the process of manufacturing a foam using a sheet-like semi-solid substance. It is sectional drawing of the box assembled using the board | plate material which affixed the sheet-like semisolid, and another board | plate material. It is sectional drawing which shows the process in which a sheet-like semisolid becomes a foam. It is a graph which shows the viscosity change in the process of manufacturing a foam using the material of embodiment of this invention. It is sectional drawing which shows the process in which a granular semi-solid becomes a foam. It is a flowchart which shows the process of shape | molding a granular semi-solid. It is a flowchart which shows the process of manufacturing a foam using a granular semi-solid. It is a graph which shows the viscosity change in the process of manufacturing a foam using the conventional material.

  Hereinafter, the thermally foamable material according to the embodiment of the present invention will be described. The thermally foamable material of this embodiment is used for producing the foam 1 shown in FIG. The foam 1 is a resin molded product in which bubbles 2 having a uniform diameter are evenly distributed, and can be used as a core material such as a desk top plate, a door, or a wing of a racing car.

  The thermally foamable material of the present embodiment used for manufacturing the foam 1 includes an epoxy resin, a low temperature curing agent, a foaming agent, and a high temperature curing agent.

  The epoxy resin is formed by mixing one or more of bisphenol type epoxy resin, novolac type epoxy resin, glycidylamine type epoxy resin and naphthalene type epoxy resin.

  Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and tetrabromobisphenol A type epoxy resin.

  The novolac type epoxy resin is a phenol novolac type epoxy resin, a cresol novolak type epoxy resin, or the like.

  The glycidylamine type epoxy resin is a resin such as tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, or tetraglycidylxylenediamine.

  Naphthalene type epoxy resin is liquid at room temperature. This naphthalene type epoxy resin includes one obtained by dissolving a solid one in a liquid state.

  The low-temperature curing agent starts the reaction with the epoxy resin at the first temperature in the range of 60 to 120 ° C. to increase the molecular weight.

  The low temperature curing agent is, for example, an amine adduct type latent curing agent, a solid or liquid modified amine compound, a microcapsule type latent curing accelerator, a curing agent containing polyamidoamine, or a curing agent containing polythiol.

  As the above amine adduct type latent curing agent, Amicure PN-23, PN-F, PN-23J, PN-31J, PN-40J (Ajinomoto Fine Techno Co., Ltd.) and Adeka Hardener EH5030S (Adeka Co., Ltd.) Can be used.

As the above-mentioned solid modified amine compound, Fuji Cure FXR-1020 FXR-1081 FXR-1121
FXR-1032 (manufactured by T & K TOKA Corporation) can be used.

  Further, as the above liquid modified amine compound, Fuji Cure 7001 7500 (manufactured by T & K TOKA Co., Ltd.) can be used.

As the above microcapsule type latent curing accelerator, NovaCure HX3941HP, NovaCure HX3921HP, NovaCure HX3748, NovaCure HX3742, NovaCure HX3741, NovaCure HX3721, NovaCure HX3613, NovaCure HX3088 (Asahi Kasei E-Materials Co., Ltd.) it can.

In addition, EPCLON B-065 (manufactured by DIC Corporation) can be used as a curing agent containing the above polyamidoamine.

  Moreover, Karenz MT PE1 (made by Showa Denko KK) can be used as a curing agent containing the above polythiol.

The addition amount of the low-temperature curing agent per unit volume of the thermally foamable material is preferably 1/5 to 4/5 of the optimum addition amount. When the addition amount of the low-temperature curing agent is less than 1/5 of the optimum addition amount, the effect of increasing the viscosity of the thermally foamable material becomes poor. When the addition amount of the low-temperature curing agent exceeds 4/5 of the optimum addition amount, the viscosity of the thermally foamable material becomes too high, and foaming may not be easily generated.

  The foaming agent starts thermal expansion at a second temperature in the range of 80 to 160 ° C.

  The foaming agent generates, for example, thermally expandable microcapsules encapsulating a volatile liquid with a thermoplastic polymer shell, or generates nitrogen gas, carbon dioxide gas, carbon monoxide, ammonia gas, hydrogen gas by decomposition by heating. It is a drug.

  For example, Expancel (manufactured by Nippon Philite Co., Ltd.) or Matsumoto Microsphere (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) can be used as the above-mentioned thermally expandable microcapsule.

  As a chemical | medical agent which generate | occur | produces gas by the decomposition | disassembly by the said heating, vinylol, a span cell, a cellular, a cellbon, a neoselbon, and an Exceller (Eiwa Chemical Industries Ltd.) can be used, for example.

  In addition, it is preferable that content of a foaming agent is 10-30 mass parts with respect to 100 mass parts of epoxy resins. When the content of the foaming agent is less than 10 parts by mass, a sufficient foaming amount cannot be obtained. When the content of the foaming agent exceeds 30 parts by mass, the foaming amount becomes too large, and the strength of the foam 1 may be reduced.

  The high-temperature curing agent starts reaction with the epoxy resin at a third temperature in the range of 120 to 180 ° C., increases the molecular weight, and crosslinks.

  Examples of the high-temperature curing agent include novolak resins such as phenol novolak and cresol novolak, amines containing aromatic amine isomers, dicyandiamides, imidazoles, and acid anhydrides.

In addition, it is preferable that the addition amount of the high-temperature curing agent per unit volume of the heat-foamable material is 1/5 to 4/5 of the optimum addition amount. When the addition amount of the high-temperature curing agent is less than 1/5 of the optimum addition amount, the physical properties of the foam 1 such as heat resistance due to lack of the high-temperature curing agent are deteriorated. When the addition amount of the high temperature curing agent exceeds 4/5 of the optimum addition amount, the content of the high temperature curing agent becomes excessive, resulting in a decrease in moisture resistance.

  In the thermally foamable material of the present embodiment, the second temperature at which the foaming agent starts thermal expansion is set at low temperature by appropriately setting the blending of the epoxy resin, the low temperature curing agent, the foaming agent, and the high temperature curing agent. The temperature at which the agent starts to react with the epoxy resin is higher than the first temperature, and the third temperature at which the high temperature curing agent starts to react with the epoxy resin is higher than the second temperature, and the heat at 23 ° C. The viscosity of the foamable material is 10 to 60 Pa · s. It is necessary to use a particulate foaming agent. If this particulate foaming agent is used, each foaming agent expands by independent foaming, thereby obtaining a foam having uniform cell size. On the other hand, when the foaming agent is liquid, the size of the expanded bubbles may be non-uniform. Further, in this embodiment, it is necessary to use a liquid epoxy resin by using the particulate foam material. By using this liquid epoxy resin, the viscosity of the thermally foamable material at room temperature can be applied. It can be made suitable for work and coating. The liquid epoxy resin may be obtained by dissolving a solid epoxy resin in a liquid state. Further, the low-temperature curing agent and the constant-temperature curing agent may be liquid or solid, but it is necessary to have the potential of not reacting with the epoxy resin at room temperature. The normal temperature is a temperature within a range of 23 ° C. ± 5 ° C. (18 ° C. to 28 ° C.).

  And in this embodiment, the sheet-like semi-solid 3 shown in FIG. 2 is shape | molded as an intermediate material using said heat-foamable material, and the foam 1 (FIG. 1) is then used using the semi-solid 3. ) Is manufactured. Hereinafter, with reference to FIG. 3, the process of shape | molding the sheet-like semi-solid 3 is demonstrated.

  As shown in FIG. 3, first, a kneading step is performed in which a thermally foamable material containing the above-described epoxy resin, low temperature curing agent, foaming agent, and high temperature curing agent is kneaded at room temperature.

  Next, a sheet forming step is performed to turn the kneaded thermally foamable material into a sheet-like semi-solid material. In this sheet forming step, first, the kneaded thermally foamable material is applied to the surface of the release sheet at room temperature. In this case, a heat-foamable material is applied to the surface of the release sheet with a thickness of, for example, about 1 mm using a known coater such as a blade coater, a roll coater, a bar coater, or an air knife coater. The release sheet is, for example, a sheet body made of paper or a synthetic resin, and it is preferable to apply a release agent such as silicone to the surface of the release sheet to which the resin is applied.

  Moreover, when performing said application | coating, the thermal foamable material apply | coated to the surface of a release sheet by moving a release sheet below a coater, or moving a coater above a release sheet It is preferable to scrape off the excess part of the film with a coater. By doing in this way, the thickness of the heat foamable material apply | coated to the surface of a release sheet can be made constant. In addition, moving said release sheet | seat is realizable by rotating the belt in which a release sheet | seat is mounted by power, such as a motor. Moreover, moving said coater is realizable by moving the suspending means which suspends a coater with motive power, such as a motor, for example.

In the sheet forming step, the release sheet coated with the heat-foamable material is further charged into the dryer, and the release sheet is heated in an atmosphere of the first temperature to the second temperature. This heating causes a reaction between the low-temperature curing agent contained in the thermally foamable material and the epoxy resin to increase the viscosity of the thermally foamable material to a viscosity range suitable for foaming. And after this heating, a release sheet is cooled to normal temperature, and the heat-foamable material with which the viscosity was raised is made into a sheet form. In the heating and cooling described above, the heating temperature / heating time in the dryer, the cooling time after heating, etc. are adjusted according to the blending of the epoxy resin, the low-temperature curing agent, the foaming agent, and the high-temperature curing agent. Thus, a sheet-like semi-solid 3 having a viscosity of 200 to 800 Pa · s at 60 ° C. is formed. This semi-solid 3 has a viscosity range that flows at the time of foaming and does not cause separation of the resin layer and the foamed layer, and can maintain a state where the foaming agent in the resin is uniformly dispersed. In addition, it is preferable that the heating temperature (atmosphere temperature in a dryer) in said sheet forming process shall be 60-120 degreeC, and heating time shall be 1 to 120 minutes. When the heating temperature is less than 60 ° C., the low temperature curing agent does not react and the viscosity of the thermally foamable material does not increase. If the heating temperature exceeds 120 ° C, the foaming agent may start to expand during heating.

  Subsequently, the peeling process which peels the sheet-like semi-solid 3 from a release sheet is implemented. Thus, the sheet-like semisolid 3 shown in FIG. 2 is obtained.

  Next, with reference to FIG. 4, the process of manufacturing the foam 1 shown in FIG. 1 using the sheet-like semi-solid 3 shown in FIG. 2 is demonstrated.

  As shown in FIG. 4, first, a sticking step of sticking the sheet-like semi-solid 3 to the surface of the plate material 5 (FIG. 5 described later) is performed. The plate material 5 is a carbon fiber prepreg obtained by adding an epoxy resin, a phenol resin, or an unsaturated polyester resin to a carbon fiber fiber material. The resin contained in the fiber material is in a semi-cured state (a state in which the curing reaction has progressed partially after the solvent has evaporated and the volatile content has disappeared), and is semi-solid with tackiness on the surface at room temperature. Therefore, it is in a solid state.

  Next, an assembling step for assembling the box 7 shown in FIG. 5 is performed by combining the plate material 5 (hereinafter referred to as the sticking plate material 5) to which the sheet-like semi-solid material 3 is attached and the other plate material 6. . In the box 7, the upper wall and the lower wall are constituted by the sticking plate material 5, and the side wall connecting the upper wall and the lower wall is constituted by another plate material 6. The box 7 has an internal space 8 surrounded by the sticking plate material 5 and the plate material 6, and the semi-solid material 3 is attached to the wall surface of the internal space 8 (the upper surface of the internal space 8). (The inner surface of the upper wall) or the bottom surface of the internal space 8 (the inner surface of the lower wall) is a semi-solid 3 is affixed). The plate material 6 is made of a carbon fiber prepreg, like the sticking plate material 5. Further, the plate members 5 and 6 constituting the box body 7 are joined and integrated by a known means / method such as a screw, an adhesive, and a concave / convex fitting. In the above-described pasting step, the semi-solid 3 to be pasted on the pasting plate material 5 has a thickness that can fill the internal space 8 by expansion (expansion) due to foaming. As in the example of FIG. 5, when the semi-solid material 3 is attached to the upper surface and the bottom surface of the internal space 8, each of the semi-solid materials 3 is expanded (expanded) by foaming, and 1 of the internal space 8. The thickness is such that / 2.

  Next, as shown in FIG. 4, a foam hardening process for heating the box body 7 is performed by putting the box body 7 into a mold having an atmosphere of a third temperature or higher (for example, 130 ° C.). The box 7 is heated for 60 minutes under an atmosphere). While the foam curing step is performed, first, the temperature of the semi-solid 3 reaches the second temperature, whereby the thermal expansion of the foaming agent occurs, and the sheet-like semi-solid 3 becomes the foam 1. . In this case, since the plate material 6 surrounds the side of the foam 1 (semi-solid 3), the foam 1 (semi-solid) due to the thermal expansion of the foaming agent as shown in FIG. 6 (a). The expansion of 3) occurs in the vertical direction. And since the thickness of the semi-solid 3 stuck to the sticking board material 5 by the past sticking process was adjusted, as shown in FIG.6 (b), the internal space 8 of the box 7 is the foam 1. Until filled, expansion of the foam 1 occurs due to thermal expansion of the foaming agent. When the temperature of the foam 1 reaches the third temperature, a reaction between the high-temperature curing agent contained in the foam 1 and the epoxy resin occurs, and the foam 1 is cured. This completes the production of the foam 1.

  Moreover, in said foam hardening process, the carbon fiber prepreg which comprises the board | plate materials 5 and 6 is also heated, and the semi-hardened resin contained in the said carbon fiber prepreg is also hardened. That is, the resin contained in the carbon fiber prepreg is once melted and then gelled and cured as the polymerization and crosslinking reaction proceed. By this curing, the plate members 5 and 6 which were carbon fiber prepregs become FRP (fiber reinforced plastic).

  Then, by the foam curing step, the solid body 3 becomes the foam 1 that has been cured, and the plate members 5 and 6 that were the carbon fiber prepregs become FRP. The range which becomes the core material is the molded body 100 (FIG. 6B) configured from the foam 1. This molded body 100 can be used as a table top, a door, a wing of a racing car, etc. (FIG. 1 is an enlarged view of the foam 1 contained in the molded body 100 alone. ).

  According to this embodiment, the foam 1 can be manufactured without requiring labor. Hereinafter, the reason will be described with reference to FIG. FIG. 7 is a graph showing the change over time in the viscosity of the thermally foamable material of the present embodiment.

  Since the heat-foamable material has an initial viscosity of 10 to 60 Pa · s at 23 ° C., the viscosity at normal temperature (23 ° C. ± 5 ° C.) is in a viscosity range suitable for kneading. Therefore, in the kneading step, the epoxy resin, the low temperature curing agent, the foaming agent, and the high temperature curing agent contained in the thermally foamable material can be kneaded at room temperature (A in FIG. 7). Therefore, unlike the heating in the kneading step (A in FIG. 11) of Patent Document 1 (Japanese Patent Laid-Open No. 2015-101670) described above, heating to lower the viscosity of the thermally foamable material to a viscosity range suitable for kneading is not required. .

  Furthermore, since the thermally foamable material contains a liquid epoxy resin, the viscosity of the thermally foamable material at room temperature can be adjusted to a viscosity range suitable for coating and coating by the kneading process (FIG. 7). A). For this reason, in the next sheet forming step, the thermally foamable material can be applied to the release sheet at room temperature (FIG. 7B), and as in the heating of the sheet forming step of Patent Document 1 (FIG. 11C), No heating is required to reduce the viscosity of the thermally foamable material to a viscosity range suitable for coating and coating.

  And further, the chemical reaction between the low-temperature curing agent and the epoxy resin occurs due to the heating in the sheeting step, and the viscosity of the thermally foamable material is increased to a viscosity range suitable for foaming (200 to 800 Pa · s at 60 ° C.), By subsequent cooling, the thermally foamable material becomes a sheet-like semi-solid 3 having a viscosity range suitable for foaming (C in FIG. 7). Therefore, after obtaining the semi-solid 3, the viscosity of the sheet (sheet-like semi-solid 3) is adjusted to a viscosity range suitable for foaming as in the thickening step (E in FIG. 11) of Patent Document 1. Does not require heating.

  Further, in the foam curing step, the thermal expansion of the foaming agent and the reaction between the high-temperature curing agent and the epoxy resin are achieved by simply heating the temperature control so that the inside of the mold is set to the third temperature or higher (D in FIG. 7). And the semi-solid 3 becomes the foam 1 and is cured.

  For the above reasons, according to the thermally foamable material of the present embodiment, it is only necessary to perform heating in only two steps of the sheet forming step and the foam curing step (C and D in FIG. 7). Compared to, the number of heating can be reduced. Further, since the semi-solid 3 having a viscosity range suitable for foaming is obtained continuously by the sheeting process, the subsequent heating in the foam curing process can be easily temperature-controlled. From the above, according to the thermally foamable material of the present embodiment, the foam 1 can be manufactured without requiring labor. Moreover, according to the semi-solid 3 of this embodiment, since the foam 1 can be manufactured only by heating in the foam curing process with easy temperature control, those who have received the semi-solid 3 from the manufacturer are extremely The foam 1 can be easily obtained.

According to the thermally foamable material of the present embodiment, the sheet-like semisolid 3 having a viscosity suitable for foaming can be stably molded for the following reasons (1) and (2).
(1) Operations from kneading to application to the release sheet (A and B in FIG. 7) can be performed at room temperature. For this reason, the thermal foaming resin applied to the release sheet does not cause a curing reaction or foaming, and has no difference in thermal history.
(2) By performing heating and cooling in the sheet forming step (C in FIG. 7), the viscosity of the thermally foamed resin is suitable for foaming by a chemical reaction between the low temperature curing agent and the epoxy resin (200 ° C. at 200 ° C.). The heat-foamed resin can be formed into a sheet in a state where the viscosity is increased in this way.

  And according to the semi-solid 3 molded from the thermally foamable material of the present embodiment, it contains a particulate foaming agent that causes independent foaming, and has a viscosity suitable for foaming (that is, The foaming agent in the resin is uniformly dispersed so as not to cause separation of the resin layer and the foamed layer), and by heating in the foam curing step (D in FIG. 7), semi-solid Bubbles 2 of uniform size are generated at each part of the object 3, and each of the bubbles 2 stays at the position where it is generated. Therefore, the foam 1 in which the uniform-sized bubbles 2 are evenly distributed can be obtained.

  According to the present embodiment, the thermally foamable material (corresponding to the sheet-like semisolid 3) is fixed to the plate 5 by sticking the sheet-like semisolid 3 to the plate 5. For this reason, unlike the case where the liquid foamable material is applied to the plate material, the foamable material does not flow on the plate material. Therefore, since the coating thickness of the heat-foamable material (corresponding to the sheet-like semisolid 3) can be maintained constant, the desired thickness can be obtained by foaming and curing the heat-foamable material (sheet-like semisolid 3). The foam 1 having the thickness can be obtained with certainty.

  Moreover, according to this embodiment, simultaneously with completion of the foam 1, a molded body 100 whose outer shell is made of FRP and whose inner core material is made of the foam 1 is obtained. Therefore, according to the present embodiment, it is possible to easily obtain a molded body that can be used as a table top, a door, or the like without the need to join the foam 1 to the FRP.

  In addition, this invention is not limited to the said embodiment, A various change can be made in a claim.

  For example, in the above-described embodiment, an example in which the plate members 5 and 6 constituting the box body 7 are carbon fiber prepregs has been shown, but the box body 7 may be constituted by prepregs containing fibers other than carbon fibers, or The box 7 may be formed of a molded product other than the prepreg (that is, the adhesive plate material 5 to which the semi-solid 3 is attached, and the other plate material 6 combined with the adhesive plate material 5 are made of fibers other than carbon fibers. It may be constituted by a prepreg containing or a molded product other than the prepreg).

  Moreover, in the said embodiment, although the example which comprises the upper wall and lower wall of the box 7 with the sticking board material 5 (plate material 5 which stuck the semi-solid 3) was shown, every wall of the box 7 is a sticking board material. 5 can be configured. In addition, if the upper wall and lower wall of the box 7 are comprised by the sticking board | plate material 5 which affixed the semisolid 3 like FIG. 5, the expansion of the foam 1 (semisolid 3) by expansion | swelling of a foaming agent will be carried out. However, it arises so that it may approach from the upper side and lower side of the internal space 8, and the internal space 8 can be obstruct | occluded with the foam 1 because the upper and lower foams 1 (semi-solid 3) meet. Thereby, a solid and high-strength molded body can be obtained.

  Further, as in the example of FIG. 5, it is not always necessary to configure the box 7 using a plurality of plate materials, and a single plate material to which the semi-solid material 3 is attached is put into the mold and heated. The solid body 3 may be foamed and cured to obtain a foam.

  Moreover, a foam may be manufactured using the granular semi-solid 10 shown to Fig.8 (a) instead of using the sheet-like semi-solid 3. FIG. In this case, the granular semi-solid 10 is formed from the step shown in FIG. 9, and the foam 20 shown in FIG. 8B is manufactured using the granular semi-solid 10 from the step shown in FIG. Hereinafter, the process shown in FIG. 9 and the process shown in FIG. 10 will be described.

  When the granular semisolid 10 is formed, a kneading step, a sheeting step, and a peeling step are first performed as in the case of forming the sheet-like semisolid 3 (FIG. 9). That is, in the kneading step, a thermally foamable material containing an epoxy resin, a low temperature curing agent, a foaming agent, and a high temperature curing agent is kneaded at room temperature. In the sheet forming step, the kneaded heat-foamable material is applied to the surface of the release sheet at room temperature, and the release sheet to which the heat-foamable material is applied is not lower than the first temperature and not higher than the second temperature. After heating in an atmosphere and cooling the thermally foamable material thereafter, the thermally foamable material is made into a sheet-like semisolid having a viscosity at 60 ° C. of 200 to 800 Pa · s. In the peeling step, the sheet-like semi-solid material is peeled from the release sheet.

  And a shredding process is implemented after a peeling process. In this shredding step, the sheet-like semi-solid material is shredded, and each of the shredded materials is granulated with a predetermined particle size by a known granulator, whereby the granular semi-solid material 10 is formed. . As described above, the granular semi-solid 10 is obtained.

  And when manufacturing the foam 20 using the granular semi-solid 10, as shown in FIG. 10, the board | plate material 50 in which the recessed part 51 was formed in the surface first was prepared, and the granular semi-solid 10 was prepared. A charging step for charging the concave portion 51 of the plate member 50 is performed (FIG. 8A). The board | plate material 50 is comprised by molded articles other than a prepreg and prepreg similarly to the board | plate materials 5 and 6 shown in said embodiment.

  Next, a foam curing process is performed in which the plate material 50 in which the semi-solid material 10 is put into the recess 51 is put into the mold and the inside of the mold is heated to a third temperature or higher. Thereby, the thermal expansion of the foaming agent contained in the semi-solid 10 occurs, and the semi-solid 10 becomes the foam 20, and thereafter, the reaction between the high-temperature curing agent contained in the foam 20 and the epoxy resin occurs. Thus, the foam 20 is cured. The foam 20 is obtained as described above.

  As described above, when the granular semi-solid 10 is formed from the thermally foamable material, the foam 20 having a shape corresponding to the recess 51 of the plate member 50 can be manufactured, and the recess 51 is filled with the foam 20 without any gap. A molded product can be obtained. In addition, the granular semi-solid 10 is applicable not only to the board | plate material 50 in which the recessed part 51 shown in FIG. 8 was formed but to the box comprised from several board | plate materials as shown in FIG. For example, when the box has a curved bottom (when the bottom of the internal space of the box is curved), according to the sheet-like semi-solid, it is difficult to attach to the bottom, According to the granular semi-solid 10, the irregularities on the bottom surface can be filled, so that a molded body in which the internal space of the box is filled with a foam without gaps can be obtained.

1,20 Foam 3,10 Semi-solid 5, 6,50 Plate 7 Box 8 Box internal space 51 Recess

Claims (14)

A thermally foamable material used to produce a foam,
Epoxy resin,
A low temperature curing agent that initiates reaction with the epoxy resin at a first temperature;
A blowing agent that initiates thermal expansion at a second temperature;
A high temperature curing agent that initiates reaction with the epoxy resin at a third temperature,
The first temperature is in the range of 60 to 120 ° C, the second temperature is in the range of 80 to 160 ° C, the third temperature is in the range of 120 to 180 ° C, and the second temperature Is higher than the first temperature, the third temperature is higher than the second temperature,
The thermally foamable material has a viscosity at 23 ° C. of 10 to 60 Pa · s,
The thermal foamable material is heated to the first temperature or higher and the second temperature or lower to cause a reaction between the low temperature curing agent and the epoxy resin, and then the thermal foamable material is cooled, The thermally foamable material can be a semi-solid material having a viscosity at 60 ° C. of 200 to 800 Pa · s,
Heating the semi-solid to the third temperature or higher causes thermal expansion of the foaming agent to make the semi-solid into a foam, and causes a reaction between the high-temperature curing agent and the epoxy resin. A thermally foamable material capable of curing the foam. The epoxy resin is formed by mixing one or more of bisphenol type epoxy resin, novolac type epoxy resin, glycidylamine type epoxy resin, naphthalene type epoxy resin,
The low-temperature curing material is either an amine adduct type curing agent or a microcapsule type curing agent,
The high-temperature curing agent is a novolak resin, amines, dicyandiamides, imidazoles, or acid anhydrides,
The foaming agent is a thermally expandable microcapsule encapsulating a volatile liquid in a thermoplastic polymer shell, or a chemical agent that generates nitrogen gas, carbon dioxide gas, carbon monoxide, ammonia gas, or hydrogen gas when decomposed by heating. The thermally foamable material according to claim 1, wherein   Content of the said foaming agent is a heat-foamable material of Claim 1 or 2 which is 10-30 mass parts with respect to 100 mass parts of said epoxy resins. The epoxy resin is liquid,
The foaming agent is particulate,
The thermal foaming according to any one of claims 1 to 3, wherein the low-temperature curing material and the high-temperature curing agent are in a liquid or solid state and have a potential of not reacting with an epoxy resin at 18 ° C to 23 ° C. Sex material. A semi-solid material formed from the thermally foamable material according to any one of claims 1 to 4 and used to produce a foam,
A semi-solid material having a viscosity at 60 ° C. of 200 to 800 Pa · s due to the reaction between the low-temperature curing agent and the epoxy resin.   The semi-solid material according to claim 5, which has a sheet shape.   The semi-solid material according to claim 5, which exhibits a granular shape. A method for forming the sheet-like semi-solid material according to claim 6,
A kneading step of kneading the thermally foamable material according to claim 1;
The kneaded thermal foamable material is applied to the surface of the release sheet, and the release sheet coated with the thermal foamable material is heated in an atmosphere of the first temperature or higher and the second temperature or lower. Thus, the reaction between the low-temperature curing agent and the epoxy resin contained in the thermally foamable material is caused, and then the thermally foamable material is cooled, so that the thermally foamable material is heated to 60 ° C. A sheet forming step for forming a sheet-like semi-solid having a viscosity of 200 to 800 Pa · s;
And a peeling step of peeling the sheet-like semi-solid from the release sheet. A method for forming the granular semi-solid according to claim 7, comprising:
A kneading step of kneading the thermally foamable material according to claim 1;
The kneaded thermal foamable material is applied to the surface of the release sheet, and the release sheet coated with the thermal foamable material is heated in an atmosphere of the first temperature or higher and the second temperature or lower. Thus, the reaction between the low-temperature curing agent and the epoxy resin contained in the thermally foamable material is caused, and then the thermally foamable material is cooled, so that the thermally foamable material is heated to 60 ° C. A sheet forming step for forming a sheet-like semi-solid having a viscosity of 200 to 800 Pa · s;
A peeling step of peeling the sheet-shaped semi-solid from the release sheet;
A molding method comprising: chopping the sheet-like semi-solid material, and forming a granular semi-solid material by making each of the chopped materials granular with a predetermined particle size.   In the application step, the release sheet moves below the blade, or the blade moves above the release sheet, so that the thermally foamable material applied to the surface of the release sheet The molding method according to claim 8 or 9, wherein an excessive portion is scraped off by the blade. A method for producing a foam using the sheet-like semi-solid material according to claim 6,
A pasting step of pasting the semi-solid material on the surface of the plate;
The plate material on which the semi-solid material is pasted is put into the mold, and the interior of the mold is heated to the third temperature or higher, thereby causing thermal expansion of the foaming agent and foaming the semi-solid material. And a foam curing step of curing the foam by causing a reaction between the high-temperature curing agent contained in the foam and the epoxy resin. By combining a plate material (hereinafter referred to as an adhesive plate material) to which the semi-solid material is attached and another plate material, the internal space is surrounded by the adhesive plate material and the other plate material, and the wall surface of the internal space And further comprising an assembly step of assembling the box to which the semi-solid material is attached,
The foam manufacturing method according to claim 11, wherein in the foam curing step, the box is put into a mold and the interior of the mold is heated to the third temperature or higher. A method for producing a foam using a granular semi-solid according to claim 11, comprising:
A charging step of charging the semi-solid into a recess formed on the surface of the plate;
Heat of the foaming agent contained in the semi-solid is obtained by putting the plate material in which the semi-solid is put into the recess into the mold and heating the inside of the mold to the third temperature or higher. A foam-curing step of causing expansion of the semi-solid to form a foam, and a reaction between the high-temperature curing agent contained in the foam and the epoxy resin to cure the foam. , Method for producing foam.   The method for producing a foam according to claim 11, wherein the plate material is a carbon fiber prepreg.

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