JP5840616B2 - Face material reinforced foam - Google Patents

Description

  The present invention is a lightweight, laminated face material made of glass fiber and thermoplastic resin on both surfaces of the foam, is excellent in moldability, particularly deep drawability, and from the face material reinforced foam. The obtained molded body relates to a face material reinforced foam excellent in dimensional stability, and a molded body obtained from the face material reinforced foam.

Conventionally, a face-reinforced foam in which a lightweight foam is used as a core material and a reinforcing face material made of a fiber material is laminated on both surfaces by a thermocompression-bonding roll is known. For example, in Patent Document 1, by using a reinforced face material having a tensile modulus of elasticity of 4 to 10 kgf / mm ² at 180 ° C. as the face material reinforcement, the deep drawability and the rigidity of the face material reinforced foam are increased, and It has been proposed to increase thermal dimensional stability.

  As a lightweight foam, a foam is known in which a thermoplastic strand is passed through a die having a plurality of discharge holes to form a foamed strand, and these are integrated. For example, U.S. Patent No. 6,057,033 discloses a die having a plurality of orifices or slits (ejection holes) arranged such that a foamable molten thermoplastic composition contacts and coalesces adjacent strands or profiles to be extruded. A process for the production of a foam having a structure in which the strands or profiles are arranged substantially parallel to the longitudinal axis of the foam is disclosed.

  It is disclosed that the foam has anisotropy in structure as compared with a general foam and has an extremely high extensibility in the direction perpendicular to the strand direction (extrusion direction).

Japanese Unexamined Patent Publication No. 8-11254 Japanese National Table 1-502252

  The face material reinforced foam described in Patent Document 1 in which reinforcing face materials are laminated on both surfaces of the foam is used. For example, the corner portion R is 10 mm, the height is 200 mm, the corner angle is 60 degrees, and the expansion rate is 200. %, Especially when molded into a deeply drawn shape, the stretchability of the face-reinforced foam at the time of molding is large, so there is no tearing in deep-drawn parts such as corners, but from this face-reinforced foam For example, when the molded body is repeatedly exposed to a high-temperature and high-humidity environment, there is a problem that molding distortion is eased and dimensional change and shape change become large.

  Further, an anisotropic foamed material such as a so-called strand converging foam described in Patent Document 2, for example, a reinforcing surface material having a high tensile elastic modulus at 180 ° C., as described in Patent Document 1. When a face material reinforced foam is produced by laminating layers, the deep drawn molded body as described above exhibits significant elongation in the vertical direction of the foam strand, but the reinforced face material is also deformed. There has been a problem that the dimensions and shape of the face material reinforced foam change.

  An object of the present invention is to provide a face material reinforced foam from which a molded article having excellent dimensional stability can be obtained even in light weight, moldability, particularly deep drawing, and a molded article obtained therefrom.

The present inventor has made extensive studies to achieve the above object, and as a result, the tensile elastic modulus is 0.7 to 1.2 kgf / mm ² which is considerably smaller than that used in Patent Document 1 and the like, and Using a reinforcing face material having a tensile elastic modulus of 0.8 to 2.0 kgf / mm ² , containing a glass fiber nonwoven fabric having an average fiber length of 15 to 100 mm in a specific range, and having an expansion ratio of 0.8 to 2.0 kgf / mm ² The face material reinforced foam laminated on both surfaces of the strand bundling foam made of 10 to 40 times uncrosslinked thermoplastic resin is excellent in light weight and moldability, and leads to a molded article excellent in dimensional stability. It has been found that this can be done, and has led to the present invention.

This invention is based on said novel knowledge, and consists of the following summaries.
1. It is a face material reinforced foam in which a reinforced face material composed of a glass fiber nonwoven fabric and a thermoplastic resin is laminated on both surfaces of a strand bundling foam made of a non-crosslinked thermoplastic resin having a foaming ratio of 10 to 40 times by a continuous strand extrusion method. The tensile elastic modulus of the glass fiber nonwoven fabric is 0.7 to 1.2 kgf / mm ² , the average fiber length of the glass fibers constituting the glass fiber nonwoven fabric is 15 to 100 mm, A face material-reinforced foam having a glass fiber content of 25 to 40% by mass and a tensile modulus of the reinforcing face material of 0.8 to 2.0 kgf / mm ² .

2. The said glass fiber nonwoven fabric is a face material reinforcement | strengthening foam of said 1 whose binder in a glass fiber nonwoven fabric is 5-20 mass% as solid content.
3. 3. The face material reinforced foam according to 1 or 2 above, which contains 0.1 to 3.0% by mass of a crosslinked resin in the solid content of the binder.
4). 4. The face material-reinforced foam according to any one of 1 to 3, wherein the glass fiber content in the face material-reinforced foam is 10 to 20% by mass.
5. 5. The face material reinforced foam according to any one of 1 to 4 above, wherein the thermoplastic resin forming the strand converging foam is a non-crosslinked polyolefin resin.

6). 6. The face material reinforced foam according to 5 above, wherein the non-crosslinked polyolefin resin is a polypropylene resin having a melt flow rate (230 ° C.) of 5 to 30 g / 10 min.
7). 7. The face material reinforced foam according to any one of 1 to 6, wherein the thermoplastic resin in the reinforced face material is a linear low density polyethylene having a density of 900 to 930 kg / m ³ .
8). The face material reinforced foam according to any one of claims 2 to 7, wherein the binder is at least one resin selected from the group consisting of a urethane resin, an acrylic resin, and a vinyl acetate resin.
9. The face material reinforced foam according to any one of the above 3 to 8, wherein the crosslinked resin is polyvinyl alcohol or a polyfunctional acrylic polyol.
10. The molded object obtained from the face material reinforcement | strengthening foam in any one of said 1-9.

ADVANTAGE OF THE INVENTION According to this invention, the surface material reinforcement | strengthening foam which can obtain the molded object excellent in lightweight property, moldability, especially deep drawing molding, and the dimensional stability is provided, and a molded object obtained therefrom.
For example, when a molded product from a face material reinforced foam is used as an automobile interior part, it is repeatedly exposed to a high humidity environment with a temperature of 90 ° C. to −40 ° C. and 95% relative humidity (RH). Even in this case, the dimensional change of the molded body is required to be less than 2 mm (dimensional change = 2/1000) with respect to the initial dimension of 1000 mm, and in a severe environment such as an automobile interior ceiling part. When used, it is required to have a dimensional change of less than 1 mm (dimensional change of less than 1/1000) with respect to an initial dimension of 1000 mm, but the present invention provides a face material-reinforced foam that can satisfy these requirements. The

(Glass fiber nonwoven fabric)
It is essential that the average fiber length of the glass fibers constituting the glass fiber nonwoven fabric is 15 to 100 mm, preferably 20 to 85 mm. When the glass fiber length is shorter than 15 mm, it is not preferable because it easily tears during molding. On the other hand, when the glass fiber length exceeds 100 mm, the variation in the fabric weight of the nonwoven fabric increases, the glass fiber tends to drop off when handling the nonwoven fabric, the workability decreases, and the nonwoven fabric is impregnated with a thermoplastic resin. This is not preferable because the resin oozes out from the nonwoven fabric.

The glass fiber nonwoven fabric used in the present invention needs to have a tensile modulus of 0.7 to 1.2 kgf / mm ² . When the tensile elastic modulus at 180 ° C. of the glass fiber material is less than 0.7 kgf / mm ² , the processability of the nonwoven fabric and the dimensional stability of the face material reinforced foam are excellent, but the stretchability of the drawn part is insufficient during molding. It is not preferable because it breaks.

On the other hand, when the tensile elastic modulus is larger than 1.2 kgf / mm ² , the moldability is very good, but the glass fiber of the nonwoven fabric is likely to drop off, and the handleability and workability are deteriorated. Residual strain increases as the material is stretched. In some cases, when handling molded products in high-temperature (low-temperature) and high-humidity environments, the strain at the time of molding is alleviated to reduce the dimensional stability of the face-reinforced foam. Is not preferable because the surface smoothness of the molded product may be impaired.
Of these, the tensile elastic modulus is more preferably 0.9 to 1.15 kgf / mm ² , and particularly preferably 0.9 to 1.1 kgf / mm ² .

It is preferable that the glass fiber nonwoven fabric used for this invention contains the binder. The gloss (ignition loss) of the binder is contained in the glass fiber nonwoven fabric in a solid content of 5 to 20% by mass, more preferably 7 to 16% by mass. If the content of the binder resin is less than 5% by mass, the binding force of the glass fibers will be weakened, resulting in an increase in fiber dropping during processing, impairing workability, and weakening the desired reinforcing effect, resulting in tearing during molding. On the other hand, if the dimensional change is large, and if it is larger than 20% by mass, the binding force between the glass fibers becomes strong, the tensile elastic modulus of the reinforcing face material is lowered, making it difficult to mold, and the nonwoven fabric becomes expensive, which is not preferable. .
The binder resin used is not particularly limited, and various binder resins such as a urethane resin, an acrylic resin, a vinyl acetate resin, and a starch (starch) can be used. Especially, as a binder resin, a vinyl acetate resin or a starch (starch) type | system | group is preferable.

Moreover, when the handling and workability of the glass fiber nonwoven fabric are taken into consideration, the binder resin may contain a cross-linked resin so as to have the tensile elastic modulus. The content of the crosslinked resin is preferably 0.1 to 3% by mass, particularly preferably 0.2 to 2% by mass, based on the solid content of the binder.
The cross-linked resin in the binder resin is not particularly limited, but polyvinyl alcohol (PVA) or polyfunctional acrylic polyol is preferably used, and polyvinyl alcohol is particularly preferable in terms of cost and processability.

(Thermoplastic resin)
As for the said glass fiber nonwoven fabric, the clearance gap between glass fibers is impregnated with the thermoplastic resin. In the present invention, the thermoplastic resin combined with the glass fiber nonwoven fabric is preferably a resin that is easily impregnated into the nonwoven fabric and has high adhesion to the foamed resin.
If the adhesiveness between the foam and the reinforced face material is insufficient, the strength of the face material reinforced foam will decrease, it will peel off during molding, and the resulting molded product will have sufficient dimensional stability. This is not preferable. The adhesive strength of the reinforcing face material and foam in 180 degree peel, preferably 0.05 kgf / mm ² or more, more preferably 0.1~5kgf / mm ^2.

Although a thermoplastic resin is not specifically limited, For example, a melt flow rate (MFR, 230 degreeC) becomes like this. Preferably it is 5-50 g / 10min, More preferably, it is 8-45 g / 10min.
The thermoplastic resin is not particularly limited, but from the viewpoint of cost, heat resistance, and ease of processing, an olefin resin, a copolymer with an ethylene resin such as EVA (ethylene-vinyl acetate copolymer), or those It is preferred to use a mixture. Among these, low density polyethylene having a density of 900 to 930 kg / m ³ is preferable, and use of linear polyethylene is preferable in terms of permeability into the nonwoven fabric, processability, and cost.

(Reinforced face material)
The reinforcing face material composed of the glass fiber nonwoven fabric and the thermoplastic resin preferably contains 25 to 40% by mass, particularly 30 to 35% by mass of glass fiber in the reinforcing face material. If the glass fiber content in the reinforcing face material exceeds 40% by mass, the tensile elastic modulus of the reinforcing face material is lowered, the elongation at the time of molding is insufficient, and the molded body is torn, which is not preferable. On the other hand, as the resin content is increased by decreasing the glass fiber content, the tensile modulus of the reinforcing face material increases and the extensibility increases. However, if the glass fiber content is less than 25% by mass, the product weight increases. Or increase in price.

  Moreover, when impregnating a thermoplastic resin with respect to a glass fiber nonwoven fabric, it is although it does not specifically limit, When a glass fiber nonwoven fabric is a sheet form, it is preferable to make it impregnate on both surfaces of a sheet | seat. However, if it is possible to reduce the non-uniformity between the thermoplastic resin having a temperature suitable for processing and appropriate viscosity characteristics and the thermoplastic resin impregnated in the thickness direction of the glass fiber nonwoven fabric, You may just impregnate from the surface.

When a reinforcing surface material having excellent extensibility by deep drawing or the like is desired, it is preferable to impregnate the glass fiber nonwoven fabric so that the thermoplastic resin is present uniformly.
Furthermore, as a method for impregnating the thermoplastic resin into the glass fiber nonwoven fabric, any apparatus that can directly impregnate the molten thermoplastic resin can be used. For example, a method in which a thermoplastic resin is combined with a glass fiber nonwoven fabric, which is an adherend, by a continuous lamination process such as a spray-type hot-melt laminating method or an extrusion laminating method of a hot-melt resin is more preferable.

  When the viscosity of the molten thermoplastic resin impregnated into the glass fiber nonwoven fabric is too high, the resin does not sufficiently penetrate into the fiber material, and it is not preferable because sufficient stretchability cannot be imparted to the reinforcing face material. On the other hand, if the viscosity of the molten thermoplastic resin is too low, the glass fiber nonwoven fabric is impregnated with the molten thermoplastic resin, and the resin oozes out from the glass fiber nonwoven fabric, which makes it difficult to process.

The reinforced face material requires a tensile elastic modulus in a high temperature tensile test set at an atmospheric temperature of 180 ° C. to be 0.8 to 2.0 kgf / mm ² , particularly 0.9 to 1.5 kgf / mm ² . Preferably there is.

When the tensile modulus at 180 ° C. of the reinforced face material is less than 0.8 kgf / mm ² , the rigidity and dimensional stability of the moldability are good, but the extensibility of the reinforced face material at the time of molding is reduced and at the time of molding. It is not preferable because tearing tends to occur.
On the other hand, when the tensile elastic modulus of the reinforcing face material exceeds 2.0 kgf / mm ² , the moldability is good, but it is preferable because the dimensional change and shape deformation of the molded body increase in the process in which the molding strain relaxes with time. Absent.

(Foam)
The resin for forming the foam in the present invention is not particularly limited, and a thermoplastic resin material is used. From the viewpoint of cost and deep drawing, it is preferable to use a non-crosslinkable polyolefin resin. Among polyolefin-based resins, it is particularly preferable to use a polypropylene-based resin that has high heat resistance and rigidity and is inexpensive. As the polypropylene resin, the melt flow rate (MFR, 230 ° C.) is preferably 5 to 30 g / 10 min, more preferably 5 to 20 g / 10 min.

  Although the strand bundling body in this invention is not specifically limited, It can be obtained by the strand continuous extrusion foaming method discharged from the several die nozzle. For example, the foam uses an extruder having a multi-hole die having an opening diameter of 0.5 to 3 mm and a numerical aperture of 50 to 5000, and at a melt extrusion temperature of 160 to 250 ° C. The discharge amount V per opening is 0.03 to 0.5 kg / h, and it is obtained by a method of extrusion foaming by releasing the nearest resin pressure of the die opening to 3-20 MPa in the atmosphere.

  However, when a strand converging foam is used for the foam, the material has anisotropy in which the tensile elongation in the vertical direction is higher than the tensile elongation in the extrusion direction of the foam.

  In the present invention, the expansion ratio of the foam is 10 to 40 times, preferably 13 to 30 times. When the expansion ratio is less than 10 times, the rigidity of the face material-reinforced foam is good, but it is not preferable because the lightness is impaired. When the expansion ratio exceeds 40 times, it is favorable in terms of lightness and cost of the face material-reinforced foam, but it is not preferable because rigidity cannot be imparted and dimensional stability is impaired.

(Face material reinforced foam)
The face material reinforced foam in the present invention is produced by laminating a reinforced face material on both surfaces of the foam, and the shape of the face material reinforced foam may be a board shape or a sheet shape.
The method of laminating the foam and the reinforced face material is not particularly limited, but the thermoplastic resin is appropriately exuded to the back surface of the glass fiber nonwoven fabric while impregnating the glass fiber nonwoven fabric with the thermoplastic resin. A method of laminating a reinforcing face material and a foam using the adhesive property of the above, a reinforcing face material obtained by impregnating a glass fiber nonwoven fabric with a thermoplastic resin, and a foam to be laminated thereon are prepared in advance. In the next step, there are a method of laminating both by a hot roll, a method of laminating both by hot air laminating, and the like.

  As a method of laminating a foam with a thermoplastic resin combined with a nonwoven fabric, there are an extrusion laminating method and a spray hot melt laminating method. The extrusion laminating method has a disadvantage that the apparatus is large and requires a wide space, and the apparatus cost is very high, but there is an advantage that a high basis weight thermoplastic resin can be easily applied with a relatively uniform basis weight. The spray-type hot melt laminating method can be processed at a relatively low cost, but has a demerit that the basis weight of the thermoplastic resin is not uniform or is not suitable for application of a high basis weight resin.

Also, when the reinforcing face material is prepared in advance, it can be suitably processed by the above extrusion laminating method or spray hot melt laminating method.
Moreover, the method of bonding the reinforcement surface material prepared beforehand by a hot roll is the method of bonding by pressing with the heated roll in the state which accumulated the reinforcement surface material on both surfaces of the foam.

  In the case of bonding with a hot roll, there is a merit that the processing method is simple, but when the thickness of the reinforced face material is thick, a large amount of heat is applied to melt the thermoplastic resin that can sufficiently adhere to the foam. It will be necessary. As a result, there are disadvantages such as increasing the amount of heat of the heat roll, increasing the size of the heat roll, requiring a plurality of heat rolls, and reducing the processing speed.

The method of pasting together the prepared reinforcing face material by hot air laminating is to blow hot air simultaneously on the foam and the reinforcing face material to soften and melt the resin on each surface, and then to cool the respective interfaces with a cooling roll It is the method of pasting together while pushing and cooling.
In the case of a hot-air laminate, the apparatus is complicated in design, and there is a demerit that high-temperature hot air must be blown to sufficiently soften and melt the material. However, when the equipment is inexpensive and does not take up space, and it is desired to homogenize the heating temperature in the product width direction, it is relatively easy to control and the thermoplastic resin impregnated in the foam and reinforced face material is heated and melted simultaneously. Therefore, even when the processing speed is high, there is an advantage that the bonding can be sufficiently performed.

The face material reinforced foam obtained as described above can be further subjected to stamping molding or vacuum molding in a subsequent step.
In the case of stamping molding, the base material is softened and melted by preheating and formed into a specific shape by a cooling press, but an adhesive layer is previously laminated on the surface of the molded body, and simultaneously with the press, on the surface of the base material, Cosmetic materials such as felt, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPR), olefin-based elastomer (TPO) sheets represented by butyl rubber grafted polyethylene and the like can be bonded together. In addition, in the process of processing the reinforcing face material, a highly transferable resin such as olefin resin such as polypropylene or polyethylene or the above-mentioned olefin elastomer is melted and cast on the surface of the glass fiber non-woven fabric. It is also possible to produce a face material reinforced foam by using this, and to transfer the uneven shape of the mold onto the surface of the molded product during press molding to give a design.

In the case of vacuum molding as well, as described above, the mold shape is transferred by pasting the decorative material on the molded product at the same time as molding, or by combining a resin with high transferability in the process of processing the reinforcing face material in advance. You can turn on.
In the face material reinforced foam, the content of glass fiber is preferably 10 to 20% by mass, more preferably 12 to 18% by mass, based on the total mass of the face material reinforced foam. When the glass fiber content is less than 10% by mass, the thermal dimensional stability of the molded product is impaired. For example, when it is used in a severe temperature and humidity environment such as an automobile interior material, the face material reinforced foam This is not preferable because it causes problems such as shrinkage of dimensions and collapse of the shape. In particular, in the case of a deep-drawn molded product having a large molding distortion, the residual stress becomes large, so that the dimensional shape stability and shape stability are significantly impaired.

  On the other hand, when the glass fiber content exceeds 20% by mass, the dimensional stability of the face material-reinforced foam can be improved, but the lightness is impaired, or the tensile elastic modulus of the reinforced face material becomes too high. This is not preferable because tearing occurs during molding.

In the present invention, various physical property values are obtained as follows.
1. The basis weight of the glass fiber nonwoven fabric was cut into a plate shape having dimensions of 200 mm in length and 200 mm in width, the mass (g) was measured with an electronic balance to the last two digits, and the basis weight of the glass fiber nonwoven fabric was calculated by the following formula. The average value (n = 5) of the calculated basis weight was used as the basis weight of the glass fiber nonwoven fabric.

Glass fiber nonwoven fabric basis weight (g / m ² )
= Mass (g) / (200 (m) / 1000 (m) × 200 (m) / 1000 (m))

2. Basis weight of reinforced face material The reinforced face material is cut into a plate shape with dimensions of 200 mm in length and 200 mm in width, the mass (g) is measured to the last two digits with an electronic balance, and the basis weight of the reinforced face material is calculated by the following formula. did. The average value (n = 5) of the calculated basis weight was used as the reinforced face material basis weight.

Reinforced face material weight (g / m ² )
= Mass (g) / (200 (m) / 1000 (m) × 200 (m) / 1000 (m))

3. Surface material reinforced foam basis weight The face material reinforced foam is cut into a plate shape with dimensions of 200 mm in length and 200 mm in width, and its mass (g) is measured to the last two digits with an electronic balance. The basis weight of the foam was calculated. The average value (n = 5) of the calculated basis weight was defined as the face material reinforced foam basis weight.

Face material reinforced foam basis weight (g / m ² )
= Mass (g) / (200/1000 (m) × 200/1000 (m))

4). Thickness of the face material reinforced foam From the flat part of the face material reinforced foam, the test piece was cut into a plate shape of 200 mm in length and 200 mm in width, and the thickness was measured to the last two digits with a digital caliper. n = 5) was defined as the thickness of the face material reinforced foam.

5. Tensile modulus and tensile elongation of glass fiber non-woven fabric at 180 ° C. Glass fiber non-woven fabric is cut into a plate shape with dimensions of 200 mm length and 25 mm width, and the non-woven fabric heated to 180 ° C. in advance to a high-temperature tensile test device with a chuck interval of 150 mm The tensile modulus was calculated by the following formula using the maximum load (kgf) and the specimen area (mm) when the specimen was pulled at a tensile speed of 50 mm / min. The average value (n = 5) of the obtained tensile elastic modulus was taken as the tensile elastic modulus at 180 ° C. of the nonwoven fabric.

180 ° C. tensile modulus (kgf / mm ² ) =
((Maximum load (kgf) / (test specimen width 25 (mm)) × chuck interval 150 (mm) × tensile elongation (%))

Moreover, in the 180 degreeC tensile test of a nonwoven fabric, the tensile elongation in 180 degreeC was computed using the following formula | equation from the displacement amount (mm) until a nonwoven fabric fractures | ruptures, and the chuck | zipper space | interval (mm) of a test.

180 ° C tensile elongation (%)
= (Displacement amount until the nonwoven fabric breaks (mm) ÷ Chuck interval (mm)) × 100

The average value (n = 5) of the obtained tensile elongation was defined as the tensile elongation at 180 ° C.

6). The tensile modulus and tensile elongation of the reinforced face material at 180 ° C. are the same as those in 5. above. The tensile elastic modulus and tensile elongation at 180 ° C. of the reinforcing face material were calculated by the same method as the 180 ° C. tensile test of the glass fiber nonwoven fabric described in 1. above.

7). Content of Glass Fiber in Reinforced Face Material The reinforced face material was cut into a plate shape having dimensions of 30 mm in length and 30 mm in width, and a material from which moisture was sufficiently removed was used as a test piece. This test piece is put in a magnetic dish (mass: W ₀ ), and the total mass (w ₁ ) of the test piece and the magnetic dish is measured to the last 4 digits with an electronic balance, and it is placed in an electric furnace set at 450 ° C. for 5 hours. Let stand, lower the temperature to room temperature in a desiccator containing silica gel, measure the mass (w ₂ ) of the magnetic dish with the reinforcing face material remaining after combustion of organic components to the last 4 digits with an electronic balance, and use the following formula From this, the glass fiber content of the reinforcing face material was calculated.
Test pieces were collected from different locations of the reinforcing face material, the above measurement was performed 5 times, and the average value of the obtained glass fiber contents was taken as the glass fiber content in the reinforcing face material.
Glass fiber content (% by mass) in reinforced face material

= ((W ₂ −W ₀ ) / (W ₁ −W ₀ )) × 100

8). Deep-drawing formability A plate-shaped face material reinforced foam having dimensions of 2400 mm in length and 1500 mm in width, in which reinforced face materials are laminated on both surfaces of the foam, was used. Four sides were clamped and fixed at a position of 50 mm at the end, and after sufficiently softening and melting by pre-heating in a far-infrared heating furnace, the face material-reinforced foam was quickly conveyed into the mold.
The mold has a square pyramid shape with a central part of 1200mm in length, 1000mm in width, and a hypotenuse of 200mm. The upper surface of the mold is concave and the lower surface is convex. A mold that is 60 degrees was used. The molded product is produced by pressing the above-mentioned softened and melted face material reinforced foam while clamping the clearance between the molds to 5.5 mm, and strengthens the face material at all deep drawing (corner, standing wall) sites. The foam was evaluated for tearing.
In the evaluation, as the method of tearing the face material reinforced foam, when the length is 100 mm or more, “large tear”, when the length is 100 to 10 mm, “medium torn”, When the foam or both were torn about 10 to 5 mm in length and a hole was formed, it was evaluated as “small tear”.

9. Dimensional stability First, the plane part of the face material reinforced foam molded by the method described in the above deep drawing moldability is marked with a straight line of 1000 mm at three vertical positions and 750 mm at three horizontal positions, On the inclined part, straight lines of 750 mm and 150 mm were written in both the vertical and horizontal directions, and the initial length (L ₀ ) of the straight line was measured by a scale with a minimum step of 0.5 mm.
Next, using a high-humidity thermostatic chamber with a set temperature accuracy of ± 1 ° C. and a set humidity accuracy of ± 2% RH, four cycles of the humidity-cooling heat cycle test were performed under the following temperature and humidity conditions.
The cycle of the wet and cold heat cycle test is as follows.
First, it is maintained at a temperature of 23 ° C. and a humidity of 50% for 0.5 hours (hereinafter referred to as initial conditions), and then at a temperature of 90 ° C. for 11.5 hours. After that, it is kept at −40 ° C. for 7.5 hours through the initial conditions, and again through the initial conditions, and kept at a temperature of 70 ° C. and a humidity of 50% for 7.5 hours. After that, the initial condition is maintained at −40 ° C. for 7.5 hours to return to the initial condition, which is one cycle.

After completion of the test, the length (L ₁ ) after the test was measured using 0.5 mm as the minimum step for each of the straight lines marked before the test.
After evaluating all the straight lines, the dimensional change after the thermal cycle test was calculated by the following formula.

Dimensional change after cooling cycle test (× 1/1000)
= ((L ₀ −l ₁ ) ÷ L ₀ ) × 1000

Further, the longitudinal change (extrusion foaming line direction: 2400 mm) of the face material reinforced foam is MD direction, and the transverse direction (width direction with respect to the extrusion foaming line: 1500 mm) is TD direction, and the dimensional change calculated in both MD direction and TD direction. The average value of these values was calculated, and this was taken as the dimensional change after the thermal cycle test of the face material reinforced foam.
In addition, as a unit of dimensional change x 1/1000, it means a deformation amount (mm) in which a molded body having an initial dimension of 1000 mm is deformed after a thermal cycle test, and has the same meaning as dimensional change rate x 0.1 (%). is there.

In the evaluation of the dimensional stability of the deep-drawn face material reinforced foam, a dimensional change of less than (1.0) × 1/1000 is “」 ”, and (1.0 to 1.5) × 1/1000 is“ ◯ ”. ”, (1.5 to 2.0) × 1/1000 was evaluated as“ Δ ”, and when the dimensional change exceeded (2.0 × 1) / 1000, it was evaluated as“ × ”.
As a molded body, for example, when it is intended to be used for automobile interior parts, the dimensional change is less than 2 × 1/1000, particularly passenger cars, as sufficient dimensional stability against severe changes in temperature and humidity in the vehicle environment. When used for interior use, the dimensional change needs to be less than 1 × 1/1000.

In order to describe the present invention more specifically, examples are given below, but the present invention is not limited to these examples. In the present invention, “%” is mass% unless otherwise specified.
The production conditions of the face material reinforced foams of Examples 1 to 7 and Comparative Examples 1 to 8, the evaluation results, and the like are summarized in Tables 1 and 2.

Example 1
A glass fiber nonwoven fabric having an average fiber diameter of 13 μm and an average fiber length of 25 mm is used. On the other hand, a binder made of a mixture of urethane resin and acrylic resin (mass ratio 80:20) is 10% by mass with respect to the mass of the glass fiber. attached is such that, further, the PVA as a crosslinking component to 0.5 wt% externally added relative to the weight of the binder, 200 ° C. at obtained by performing 90 seconds heat treatment, ignition at a basis weight 50 g / ^{m 2} A glass fiber nonwoven fabric with 10% weight loss (igros) was used. This glass fiber nonwoven fabric had a tensile elastic modulus at 180 ° C. of 1.0 kgf / mm ² and a tensile elongation at 180 ° C. of 0.83%.

A linear low density polyethylene resin (LLDPE, density 919 kg / m ³ MFR: 8.0 g / 10 min) as a thermoplastic resin is 50 g / m ² as a basis weight in a molten state of 280 to 290 ° C. It applied directly so that it might become. Next, the LLDPE resin is directly applied so that the basis weight of the resin is 100 g / m ^{2 in} total with a basis weight of 50 g / m ² from the back side of the glass fiber nonwoven fabric, and impregnated by an extrusion laminating method to obtain a glass content. A 33% by mass reinforcing face material was produced.
The basis weight of this reinforcing face material was 150 g / m ² and the LLDPE resin content was 67% by mass. Moreover, the tensile elasticity modulus in 180 degreeC was 1.1 kgf / mm < ² >, and the tensile elongation in 180 degreeC was 5.7%.

On the other hand, using a tandem extruder, homopolypropylene resin having an MFR at 230 ° C. of 3.3 g / 10 min and a melt tension at 230 ° C. of 7.9 g was discharged at 230 ° C. at a discharge rate of 75 kg / hour (h). And melted at a temperature setting of 6.5% by mass with respect to 100% by mass of the homopolypropylene resin. The temperature is set so that the resin temperature immediately before foaming is 185 ° C., the hole diameter is 1332 (4 holes in the thickness direction of the foam, 333 holes in the width direction), the hole diameter is 0.59 mm, and the hole interval is 4.5 mm. The product is extruded through a multi-strand die nozzle so that the resin pressure becomes 8.3 MPa, and the pressure is released to atmospheric pressure at a stretch. A foam having a double size, a thickness of 12 mm, and a basis weight of 380 g / m ² was produced.
Next, in a continuous line, hot air of 280 ° C. is blown between the reinforcing face material prepared in advance as described above and the foam to melt the LLDPE resin of the reinforcing face material and the PP (polypropylene) resin on the surface of the foam. After that, by pressing with a PTFE (polytetrafluoroethylene) coating roll promptly, a reinforcing face material was bonded to both surfaces of the foam to produce a face material reinforced foam.

The weight of the obtained face material reinforced foam was 680 g / m ² , the thickness was 11 mm, and the glass content in the face material reinforced foam was 15% by mass.
The face material reinforced foam obtained as described above is retained in a far-infrared heating furnace having a set temperature of 280 ° C. for 120 seconds and heated so that the surface temperature of the molded product becomes 170 to 180 ° C. The die was set at 30 ° C., and deep drawing was performed under the conditions of a die clearance setting of 5.5 mm.

The molded product of the obtained face material reinforced foam had no cracks at the deep drawing corner (standing wall inclined surface), and the surface appearance was beautiful.
Furthermore, when this molded body was used and the dimensional change of the molded body before and after the test was examined by the above-described cooling / heating cycle test, the dimensional change was 0.98 × 1/1000 (dimensional change rate 0.098%). It was confirmed that the stability was excellent.

Example 2
A face material reinforced foam having the same production conditions as Example 1 was obtained except that the amount of PVA added as a crosslinking component of the binder of the glass fiber nonwoven fabric was 3%.

Example 3
A face material-reinforced foam having the same production conditions as in Example 1 was obtained except that a nonwoven fabric with a basis weight of 40 g / m ² was used, although the basis weight of the glass fiber nonwoven fabric was appropriate.

Example 4
A reinforced face material having the same production conditions as in Example 1 was obtained except that a nonwoven fabric with a basis weight of 65 g / m ² was used, although the basis weight of the glass fiber nonwoven fabric was appropriate but extremely high.

Examples 5 and 6
A face material-reinforced foam having the same production conditions as in Example 1 was obtained except that the amount of the binder for binding the glass fibers was 15% by mass and 20% by mass.

Example 7
The same production conditions as in Example 1 except that the basis weight (mass per unit area) of the thermoplastic resin impregnated into the glass fiber nonwoven fabric was 38 g / m ² and the glass fiber content in the reinforcing face material was 40% by mass. A face material reinforced foam was obtained.

Comparative Example 1
A face material reinforced foam having the same production conditions as in Example 1 was obtained except that the addition amount of PVA as a crosslinking component of the binder of the glass fiber nonwoven fabric was 5%.

Comparative Example 2
A face material reinforced foam having the same production conditions as in Example 1 was obtained except that PVA which is a crosslinking component of the binder of the glass fiber nonwoven fabric was not added.

Comparative Example 3
The surface is the same production conditions as in Example 1 except that a nonwoven fabric with a basis weight of 30 g / m ² is used, and the glass fiber content contained in the reinforcing face material is 23 mass%. A material reinforced foam was obtained.

Comparative Example 4
A face material reinforced foam having the same production conditions as in Example 1 was obtained except that a glass fiber nonwoven fabric having an average fiber length of 10 mm was used.

Comparative Example 5
A face material reinforced foam having the same production conditions as in Example 1 was obtained except that a glass fiber nonwoven fabric having an average fiber length of 120 mm was used.

Comparative Example 6
A face material-reinforced foam that was the same as in Example 1 was obtained except that the amount of the binder for binding glass fibers was changed to 4% by mass.

Comparative Example 7
The same as Example 1 except that the basis weight (mass per unit area) of the thermoplastic resin impregnated into the glass fiber nonwoven fabric was 25 g / m ² and the glass fiber content in the reinforcing face material was 50% by mass. A face material reinforced foam was obtained.

Comparative Example 8
The same as Example 1 except that the basis weight (mass per unit area) of the thermoplastic resin impregnated into the glass fiber nonwoven fabric was 110 g / m ² and the glass fiber content in the reinforcing face material was 19% by mass. A face material reinforced foam was obtained.

The face material reinforced foam provided by the present invention is lightweight, excellent in moldability, particularly deep drawability, and a molded body obtained from the face material reinforced foam is excellent in dimensional stability. It is widely used as a member for vehicles such as a ceiling material for automobiles.
It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2010-206018 filed on September 14, 2010 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (10)

It is a face material reinforced foam in which a reinforced face material composed of a glass fiber nonwoven fabric and a thermoplastic resin is laminated on both surfaces of a strand bundling foam made of a non-crosslinked thermoplastic resin having a foaming ratio of 10 to 40 times by a continuous strand extrusion method. The tensile elastic modulus of the glass fiber nonwoven fabric is 0.7 to 1.2 kgf / mm ² , the average fiber length of the glass fibers constituting the glass fiber nonwoven fabric is 15 to 100 mm, A face material-reinforced foam having a glass fiber content of 25 to 40% by mass and a tensile modulus of the reinforcing face material of 0.8 to 2.0 kgf / mm ² .   The face material reinforced foam according to claim 1, wherein the glass fiber nonwoven fabric has a binder in the glass fiber nonwoven fabric in a solid content of 5 to 20% by mass.   The face material reinforced foam according to claim 1 or 2, wherein the solid content of the binder contains 0.1 to 3.0% by mass of a crosslinked resin.   The face material-reinforced foam according to any one of claims 1 to 3, wherein the glass fiber content in the face material-reinforced foam is 10 to 20% by mass. The face material reinforced foam according to any one of claims 1 to 4, wherein the thermoplastic resin forming the strand-bundled foam is a non-crosslinked polyolefin resin. The face material reinforced foam according to claim 5, wherein the non-crosslinked polyolefin resin is a polypropylene resin having a melt flow rate (230 ° C.) of 5 to 30 g / 10 min. The face material-reinforced foam according to any one of claims 1 to 6, wherein the thermoplastic resin in the reinforcing face material is a linear low density polyethylene having a density of 900 to 930 kg / m ³ .   The face material reinforced foam according to any one of claims 2 to 7, wherein the binder is at least one resin selected from the group consisting of a urethane resin, an acrylic resin, and a vinyl acetate resin.   The face material-reinforced foam according to any one of claims 3 to 8, wherein the crosslinked resin is polyvinyl alcohol or a polyfunctional acrylic polyol.   The molded object obtained by shape | molding the face material reinforcement | strengthening foam in any one of Claims 1-9.