JP6934371B2 - Resin laminated foam board, its thermoformed product and assembly box - Google Patents

Description

The present invention relates to a resin laminated foam plate, a thermoformed product thereof, and an assembly box.

Expanded polystyrene is lightweight and has excellent impact resistance. Therefore, it is widely used as a material for boxes for transporting products and parts. However, expanded polystyrene has poor oil resistance and is not suitable as a material for boxes for transporting machine products and machine parts to which oil is attached.

To solve such a problem, Patent Document 1 proposes a laminated sheet having a foamed layer of a polypropylene resin. According to the present invention, the oil resistance of a packaging container obtained by thermoforming a laminated sheet is improved.

Japanese Patent No. 4991345

However, the packaging container of Patent Document 1 does not have sufficient thermoformability and surface smoothness (appearance design) when the laminated sheet is thermoformed.
In addition, the packaging container of Patent Document 1 is intended for food use, and has insufficient strength as a box for transporting heavier machine products and machine parts.
Therefore, an object of the present invention is a resin laminated foam plate which is excellent in thermoformability and appearance design and is excellent in strength, a thermoformed product thereof, and an assembly box.

In order to solve the above problems, the present invention provides the following means.
[1] A polypropylene-based resin foamed resin layer (A), a polypropylene-based resin non-foamed resin layer (B) provided on both sides thereof, and at least one of the non-foamed resin layers (B). A resin laminated foam plate provided with a non-foamed resin layer (C) of a polyolefin-based resin or a polyester-based resin.
The foamed resin layer (A) has a closed cell ratio of 70% or more, a thickness of 2.0 to 6.0 mm, and substantially does not contain an inorganic filler.
The non-foaming resin layer (B) contains 5 to 40% by mass of the inorganic filler with respect to the total mass of the non-foaming resin layer (B).
The melting point of the resin of the non-foaming resin layer (C) is lower than the melting point of the resin of the foamed resin layer (A), and the non-foaming resin layer (B) adjacent to the non-foaming resin layer (C). Lower than the melting point of the resin
The non-foamed resin layer (C) is a resin laminated foam plate having a surface glossiness of 60% or more and a thickness of 0.02 to 0.10 mm.
[2] The melt mass flow rate (MFR) of the resin of the foamed resin layer (A) and the resin of the non-foamed resin layer (B) at 230 ° C. and 0.23 MPa is 5.0 g / 10 min or less [1]. The resin laminated foam plate described in.
[3] The method according to [1] or [2], wherein the density of the foamed resin layer (A) is 100 to 700 kg / m ³ , and the average bubble diameter of the foamed resin layer (A) is 20 to 200 μm. Resin laminated foam board.
[4] A thermoformed product obtained by thermoforming the resin laminated foam plate according to any one of [1] to [3].
[5] An assembly box in which the thermoformed product according to [4] is used as a bottom plate, and the resin laminated foam plate according to any one of [1] to [3] is used as a side plate.

According to the resin laminated foam plate of the present invention, it is excellent in thermoformability and appearance design, and is also excellent in strength.

It is sectional drawing of the resin laminated foam plate which concerns on one Embodiment of this invention. It is a perspective view of the assembly box which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line III-III of FIG.

The resin laminated foam plate (hereinafter, also referred to as a foam plate) of the present invention includes a foamed resin layer (A) of a polypropylene-based resin (hereinafter, also referred to as an A layer) and a non-foamed resin layer (B) of a polypropylene-based resin. Hereinafter, it also includes a B layer) and a non-foamed resin layer (C) of a polyolefin resin or a polyester resin (hereinafter, also referred to as a C layer). In the present specification, the C layer is also referred to as a surface resin layer.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a resin laminated foam plate according to an embodiment of the present invention. In the foam plate 1 of FIG. 1, the first B layer 20 is laminated on one surface of the A layer 10, and the first C layer 30 is laminated on the first B layer 20. In the foam plate 1, the second B layer 22 is laminated on the other surface of the A layer 10, and the second C layer 32 is laminated on the second B layer 22. The first C layer 30 and the second C layer 32 are located on the surface of the foam plate 1. That is, the first C layer 30 and the second C layer 32 are surface resin layers of the foam plate 1.
The A layer 10 and the first B layer 20 are heat-sealed. The A layer 10 and the second B layer 22 are heat-sealed. The first B layer 20 and the first C layer 30 are heat-sealed via a first adhesive layer (not shown). The second B layer 22 and the second C layer 32 are heat-sealed via a first adhesive layer (not shown).

The A layer 10 is a foamed resin layer of a polypropylene resin. The foam plate 1 is excellent in impact resistance because it includes the A layer 10.
Examples of the polypropylene-based resin constituting the layer A 10 include a propylene homopolymer (homopolypropylene resin), a copolymer with other monomers, a mixture thereof, and the like.
The polypropylene-based resin preferably contains a propylene-based structural unit in an amount of 50% by mass or more, more preferably 70% by mass or more, and 80% by mass or more based on all the structural units of the polypropylene-based resin. Is more preferable. Further, it may be 100% by mass.

As the other monomer, α-olefins other than propylene such as ethylene, 1-butylene, 1-pentyne and 1-hexene are preferable.
Examples of the copolymer include a block copolymer of propylene and other monomers, and a random copolymer of propylene and other monomers.
As the other monomer, one type may be used alone, or two or more types may be used in combination.

As the polypropylene-based resin, a high melt tension polypropylene (HMS-PP) resin is preferable. High melt tension polypropylene resin is a polypropylene resin whose tension in the molten state is increased by mixing a high molecular weight component or a component having a branched structure in the polypropylene resin or copolymerizing a long chain branched component with polypropylene. be. High melt tension polypropylene resins are commercially available, for example, "WB130HMS", "WB135HMS", "WB140HMS" manufactured by Borealis; "Pro-fax F814" manufactured by Basell; "FB3312", "FB3312" manufactured by Japan Polypropylene Corporation. FB5100 ”,“ FB7200 ”,“ FB9100 ”,“ MFX8 ”,“ MFX6 ”and the like can be mentioned.

Whether or not the polypropylene-based resin is a high melt tension polypropylene resin can be determined not only by the difference in polymer structure but also by the magnitude of the melt tension. For example, if the melt tension is 5 cN or more, it can be determined that the polypropylene resin has a high melt tension.
High melt tension The melt tension of the polypropylene resin is preferably 10 cN or more and 30 cN or less, for example. When it is at least the above lower limit value, it is easy to increase the strength of the foam plate 1. When it is not more than the above upper limit value, the thermoformability is more likely to be improved.

The melt mass flow rate (MFR) of the polypropylene-based resin of layer A 10 is preferably 5.0 g / 10 min or less, more preferably 0.1 g / 10 min or more and 5.0 g / 10 min or less, and 0.5 g / 10 min or more and 4.0 g. It is more preferably / 10 min or less. When the MFR is at least the above lower limit value, the closed cell ratio of the A layer 10 is likely to be 70% or more. When the MFR is not more than the above upper limit value, the strength of the foam plate 1 can be easily increased.
MFR is a numerical value representing the fluidity of the thermoplastic resin when it is melted. MFR is represented by the amount of resin that melts in the cylinder and is extruded by a piston from a die with a specified diameter installed at the bottom of the cylinder per 10 minutes under constant temperature and load conditions.
In the present specification, MFR is a numerical value at 230 ° C. and 0.23 MPa.

The melting point of the polypropylene-based resin of layer A 10 is preferably 150 ° C. or higher and 170 ° C. or lower, and more preferably 155 ° C. or higher and 165 ° C. or lower. When the melting point of the polypropylene-based resin of the A layer 10 is at least the above lower limit value, the strength of the foam plate 1 can be more easily increased. When the melting point of the polypropylene-based resin of the A layer 10 is not more than the above upper limit value, the thermoformability is more likely to be improved.
The melting point of the polypropylene-based resin of layer A 10 is measured by the method described in JIS K7121: 1987 “Method for measuring transition temperature of plastic”.

Layer A 10 is substantially free of inorganic fillers.
In the present specification, "substantially free of inorganic filler" means that the content of the inorganic filler with respect to the total mass of the layer A 10 is 0.1% by mass or less.
In the present specification, the inorganic filler refers to an inorganic compound used as a filler, and refers to calcium carbonate, talc, silica, clay, alumina, mica, titanium oxide, glass beads, glass balloons, carbon fibers, glass fibers, and carbon. Examples include black and metal powder.
Since the A layer 10 does not substantially contain an inorganic filler, it is lightweight and has excellent thermoformability.

The closed cell ratio of the A layer 10 is 70% or more, preferably 75% or more, and more preferably 80% or more. The upper limit is not particularly limited, and is preferably 99% or less, for example. When the closed cell ratio of the A layer 10 is within the above numerical range, the impact resistance is excellent and the thermoformability is easily improved.
The closed cell ratio of layer A 10 is measured by the method described in JIS K7138: 2006 "Hard foamed plastic-How to determine open cell ratio and closed cell ratio".

The thickness t10 of the A layer 10 is 2.0 to 6.0 mm, preferably 2.5 to 5.5 mm, and more preferably 3.0 to 5.0 mm. When the thickness t10 is at least the above lower limit value, the heat insulating performance is more likely to be improved. When the thickness t10 is not more than the above upper limit value, the thermoformability is more likely to be improved. The thickness t10 is an average value of the thicknesses of any 10 points measured by calipers.

The basis weight of the A layer 10 is preferably from 300 to 700 g / ^{m 2,} more preferably 350~650g / ^{m 2,} more preferably 400-600 g / ^{m 2.} When the basis weight of the A layer 10 is not more than the above lower limit value, the strength of the foam plate 1 can be more easily improved. When it is not more than the above upper limit value, the thermoformability is more likely to be improved. The basis weight of the A layer 10 is obtained as follows.
Except for 20 mm at both ends in the width direction (TD direction) of the A layer 10, 10 sections of 10 cm × 10 cm are cut out at equal intervals in the width direction, and the mass (g) of each section is measured up to 0.001 g. The value obtained by converting the average value of the mass (g) of each section into the mass ^{per 1 m 2 is} defined as the basis weight (g / m ² ) of the layer A 10.

The density of A layer 10 is preferably 100~700kg / ^{m 3,} more preferably 150~600kg / ^{m 3,} more preferably 150~450kg / ^{m 3.} When the density of the A layer 10 is equal to or higher than the above lower limit value, the strength can be more easily improved. When it is not more than the above upper limit value, it is easy to make the foam plate 1 lighter.

The foaming ratio of the A layer 10 is preferably 2.0 to 6.0 times, more preferably 2.0 to 5.0 times, and even more preferably 2.5 to 4.0 times. When the foaming ratio of the A layer 10 is at least the above lower limit value, the heat insulating performance is more likely to be improved. When it is not more than the above upper limit value, the thermoformability is more likely to be improved.
The foaming ratio of the A layer 10 is determined as follows.
The A layer 10 is cut out to a predetermined size and used as a sample. The size (planar viewing area: S) and thickness (t) of the sample are measured. Multiply the size and thickness of the sample to obtain the apparent volume (V = S × t (cm ³ )) of the sample. ^{The apparent density (d = M / V (g / cm 3} )) of the layer A 10 is calculated from the obtained volume and the mass (M (g)) of the sample.
Then, the density of the polypropylene-based resin forming the A layer 10 (for example, ρ: 0.90 g / cm ³ ) is divided by the apparent density (d) of the A layer 10, and the A layer 10 is foamed. Find the magnification (times).
Foaming magnification (times) = Density of polypropylene resin (ρ) ÷ Apparent density of layer A 10 (d)

The average bubble diameter of the A layer 10 is preferably 20 to 200 μm, more preferably 30 to 180 μm, and even more preferably 50 to 150 μm. When the average cell diameter of the A layer 10 is at least the above lower limit value, the thermoformability is more likely to be improved. When the average cell diameter of the A layer 10 is not more than the above upper limit value, the strength can be further improved.
The average cell diameter of layer A 10 is calculated as follows.
The foam plate 1 was cut, and the cut surface was photographed at a magnification of 18 times using a scanning electron microscope for the portion excluding the outer 1/10 in the thickness direction of the cut surface, and the photographed image of the cut surface was taken. Print on paper. Next, an arbitrary line segment (length 60 mm) is drawn at 6 points on the paper, and the average chord length for each line segment is calculated from the number of bubbles overlapping the line segments by the following formula. However, the line segment shall be drawn so that the bubbles do not come into contact with each other only at the contacts as much as possible, and if they do come into contact with each other, they shall be included in the number of bubbles.
Average chord length (t) = line segment length / (number of bubbles x photo magnification)
Then, the bubble diameter D is calculated by the following formula.
D = t / 0.616
Then, the arithmetic mean value of the bubble diameter D obtained for each line segment is obtained, and this arithmetic mean value is used as the average bubble diameter of the A layer 10.
The average cell diameter of the layer A 10 is adjusted by the type and amount of the polypropylene-based resin, and the type and amount of the foaming agent, and the combination.

Examples of the effervescent agent include inorganic degradable effervescent agents such as ammonium carbonate, sodium bicarbonate, ammonium bicarbonate, ammonium nitrite, calcium azide, sodium azide, and sodium borohydride; azodicarboxylic amide, azobissulforumamide, and azo. Azo compounds such as bisisobutyronitrile and diazoaminobenzene; nitroso compounds such as N, N'-dinitrosopennanmethylenetetramine, N, N'-dimethyl-N, N'-dinitrosoterephthalamide; benzenesulfonylhydrazide , P-Toluenesulfonyl hydrazide, p, p'-oxybisbenzsulfonyl semicarbazide, p-toluenesulfonyl semicarbazide, trihydrazinotriazine, barium azodicarboxylate and the like. Examples of the gaseous foaming agent include air, nitrogen, carbon dioxide, propane, neopentane, methyl ether, methane dichloride, n-butane, isobutane and the like. Here, the gas means a gas at room temperature (15 ° C. to 25 ° C.). On the other hand, examples of the volatile foaming agent include ether, petroleum ether, acetone, pentane, hexane, isohexane, heptane, isoheptane, benzene, toluene and the like.
Of the above foaming agents, n-butane and nitrogen are particularly preferable.
These foaming agents may be used alone or in combination of two or more.

The content of the foaming agent is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polypropylene resin.
When the foaming agent is a volatile foaming agent, the content of the volatile foaming agent is 0.5 to 100 parts by mass with respect to 100 parts by mass of the polypropylene-based resin, although it varies depending on the type of foaming agent, the desired foaming ratio, and the like. 20 parts by mass is preferable.

The layer A 10 may further contain a known foaming aid in order to adjust the decomposition temperature, the amount of gas generated and the decomposition rate. Examples of the foaming aid include solvents such as toluene, xylene, ethylbenzene, cyclohexane and D-limonene; and plasticizers (high boiling point solvents) such as diisobutyl adipate, diacetylated monolaurate and coconut oil. The content of the foaming aid is preferably 0.1 to 2.5 parts by mass with respect to 100 parts by mass of the polypropylene resin.

The A layer 10 may further contain a bubble adjusting agent. Examples of the bubble adjusting agent include an acid salt of a polyvalent carboxylic acid, a reaction mixture of the polyvalent carboxylic acid and sodium carbonate or sodium bicarbonate, and the like. Is preferably the reaction mixture described above.
The content of the bubble adjusting agent is preferably 0.01 to 1.0 part by mass with respect to 100 parts by mass of the polypropylene resin.
The layer A 10 may further contain a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant and the like, if necessary.

The first B layer 20 is a polypropylene-based resin non-foaming resin layer provided on one surface of the A layer 10. The second B layer 22 is a non-foamed resin layer of polypropylene resin provided on the other surface of the A layer 10. The foam plate 1 is likely to have improved strength by providing the first B layer 20 on one surface of the A layer 10. In addition, since the foam plate 1 is provided with the second B layer 22 on the other surface of the A layer 10, the flatness can be easily maintained and the warpage can be suppressed, so that the thermoformability can be easily improved. Further, the foam plate 1 is provided with the first B layer 20 and the second B layer 22 on both sides of the A layer 10 to conceal the unevenness of the surface of the A layer 10 (concealment property) and improve the appearance design property. Easy to improve.
In addition, since the first B layer 20 and the second B layer 22 are non-foaming resin layers of polypropylene-based resin, they are excellent in chemical resistance.

As the polypropylene-based resin constituting the first B layer 20, the same resin as the polypropylene-based resin constituting the A layer 10 can be used. As the polypropylene-based resin constituting the second B layer 22, the same resin as the polypropylene-based resin constituting the A layer 10 can be used.
The polypropylene-based resin constituting the first B layer 20 may be the same as or different from the polypropylene-based resin constituting the A layer 10. The polypropylene-based resin constituting the second B layer 22 may be the same as or different from the polypropylene-based resin constituting the A layer 10.
The polypropylene-based resin constituting the second B layer 22 may be the same as or different from the polypropylene-based resin constituting the first B layer 20.

The first B layer 20 contains an inorganic filler. In the present specification, the inorganic filler refers to an inorganic compound used as a filler, and refers to calcium carbonate, talc, silica, clay, alumina, mica, titanium oxide, glass beads, glass balloons, carbon fibers, glass fibers, and carbon. Examples include black and metal powder. As the inorganic filler used for the first B layer 20, calcium carbonate and talc are preferable.
Since the first B layer 20 contains an inorganic filler, it is more excellent in strength.

The content of the inorganic filler in the first B layer 20 is 5 to 40% by mass, preferably 10 to 35% by mass, more preferably 15 to 30% by mass, based on the total mass of the first B layer 20. preferable. When the content of the inorganic filler in the first B layer 20 is at least the above lower limit value, the strength of the foam plate 1 can be more easily improved. When the content of the inorganic filler in the first B layer 20 is not more than the above upper limit value, the appearance designability and the thermoformability are more likely to be improved.

The inorganic filler used for the second B layer 22 is the same as the inorganic filler used for the first B layer 20. The inorganic filler used for the second B layer 22 may be the same as or different from the inorganic filler used for the first B layer 20.
The content of the inorganic filler in the second B layer 22 may be the same as or different from the content of the inorganic filler in the first B layer 20.

The MFR of the polypropylene-based resin of the first layer 20 is preferably 5.0 g / 10 min or less, more preferably 0.1 g / 10 min or more and 5.0 g / 10 min or less, and 0.5 g / 10 min or more and 4.0 g / 10 min or less. The following is more preferable. When the MFR is at least the above lower limit value, the strength of the foam plate 1 can be more easily improved. When the MFR is not more than the above upper limit value, the appearance design and the thermoformability are more likely to be improved. The MFR of the polypropylene-based resin of the first layer B 20 is a numerical value at 230 ° C. and 0.23 MPa.
The MFR of the second B layer 22 may be the same as or different from the MFR of the first B layer 20.

The melting point of the polypropylene-based resin of the first layer B 20 is preferably 150 ° C. or higher and 170 ° C. or lower, and more preferably 155 ° C. or higher and 165 ° C. or lower. When the melting point of the polypropylene-based resin of the first layer B 20 is at least the above lower limit value, the strength of the foam plate 1 can be more easily increased. When the melting point of the polypropylene-based resin of the first layer B 20 is not more than the above upper limit value, the thermoformability is more likely to be improved.
The melting point of the polypropylene-based resin of the first layer B 20 can be measured by the same method as the melting point of the polypropylene-based resin of the A layer 10.
The melting point of the polypropylene-based resin of the second layer B 22 may be the same as or different from the melting point of the polypropylene-based resin of the first layer B 20.

The thickness t20 of the first B layer 20 is preferably 0.05 to 0.25 mm, more preferably 0.075 to 0.25 mm, and even more preferably 0.10 to 0.20 mm. When the thickness t20 is at least the above lower limit value, the strength of the foam plate 1 can be more easily improved. When the thickness t20 is not more than the above upper limit value, the thermoformability is more likely to be improved. The thickness t20 is obtained by the same method as the thickness t10 of the A layer 10.
The thickness t22 of the second B layer 22 may be the same as or different from the thickness t20 of the first B layer 20.

The basis weight of the first B layer 20 is preferably from 50 to 250 g / ^{m 2,} more preferably 75~225g / ^{m 2,} more preferably 100 to 200 g / ^{m 2.} When the basis weight of the first B layer 20 is not more than the above lower limit value, the strength of the foam plate 1 can be more easily improved. When it is not more than the above upper limit value, the thermoformability is more likely to be improved.
The basis weight of the second layer B 22 may be the same as or different from the basis weight of the first layer B 20.

The first C layer 30 is a non-foamed resin layer of a polyolefin resin or a polyester resin provided on the first B layer 20. The first C layer 30 is a film-like layer having a thin thickness and a glossy surface, and is located on the surface of the foam plate 1, so that the appearance design is easily improved. Further, since the first C layer 30 is composed of a resin having a melting point lower than that of the resins of the A layer 10 and the first B layer 20, it has good elongation during thermoforming, and is on the surface of the foam plate 1. The occurrence of cracks can be suppressed and the thermoformability can be easily improved. In addition, the first C layer 30 is excellent in low temperature brittleness and can suppress scratches on the surface of the foam plate 1, so that the strength of the foam plate 1 can be easily improved. The first C layer 30 functions as a surface resin layer.

The foam plate 1 includes a second C layer 32 provided on the second B layer 22. The second C layer 32 is a non-foamed resin layer of a polyolefin resin or a polyester resin.
The second C layer 32 is the same as the first C layer 30, and functions as a surface resin layer. The second C layer 32 may be the same as or different from the first C layer 30.

Examples of the polyolefin-based resin constituting the first C layer 30 include polyolefin-based resin films such as polyethylene film and polypropylene film.
Examples of the polyester-based resin constituting the first C layer 30 include polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polyethylene furanoate resin, polybutylene naphthalate resin, terephthalic acid, ethylene glycol, and cyclohexanedi. Examples thereof include copolymers with methanol, mixtures thereof, and mixtures of these with other resins. Further, a plant-derived polyethylene terephthalate resin and a polyethylene furanoate resin may be used. These polyester resins may be used alone or in combination of two or more. A particularly preferable polyester-based resin is a polyethylene terephthalate resin.
When another resin is mixed as the polyester resin, the content of the other resin is preferably less than 50% by mass with respect to the total mass of the polyester resin.
As the resin constituting the first C layer 30, a polyolefin-based resin is preferable from the viewpoint of further enhancing thermoforming property, a polypropylene-based resin is more preferable from the viewpoint of improving oil resistance, and a non-stretched polypropylene (CPP) film is preferable. More preferred.

The resin constituting the first C layer 30 is a propylene homopolymer, a copolymer in which ethylene or other comonomer is inserted in an amount of about 1 to 7% by mass in a propylene molecular chain, or usually in a matrix of a propylene homopolymer. Impact copolymers (also referred to as block copolymers) containing up to about 20% ethylene-propylene rubber (EPR) can be used alone, or mixtures thereof can also be used. Further, the film resin may be mixed with other resins as long as the effects of the present invention are not impaired. Examples of the other resin include homopolymers or copolymers such as ethylene, butene and α-olefin, olefin resins such as polyolefin wax and polyolefin elastomer, and hydrocarbon resins such as petroleum resin and terpene resin. Resins and the like are used alone or in admixture of two or more.
The resin constituting the second C layer 32 may be the same as or different from the resin constituting the first C layer 30.

The melting point of the resin constituting the first C layer 30 is lower than the melting point of the resin of the first B layer 20 adjacent to the A layer 10 and the first C layer 30. The melting point of the resin constituting the first C layer 30 is, for example, preferably 130 ° C. or higher and lower than 150 ° C., and more preferably 135 ° C. or higher and 145 ° C. or lower. When the melting point of the resin constituting the first C layer 30 is at least the above lower limit value, the low temperature brittleness of the foam plate 1 is likely to be further enhanced. When the melting point of the resin constituting the first C layer 30 is not more than the above upper limit value, the thermoformability is more likely to be improved.
The melting point of the resin constituting the first C layer 30 can be measured by the same method as the melting point of the polypropylene-based resin of the A layer 10.
The melting point of the resin constituting the second C layer 32 may be the same as or different from the melting point of the resin constituting the first C layer 30.

The surface glossiness of the first C layer 30 is 60% or more, preferably 70% or more, more preferably 80% or more, still more preferably 90% or more. The upper limit of the surface glossiness of the first C layer 30 is not particularly limited, and is preferably 99% or less, for example.
When the surface glossiness of the first C layer 30 is within the above numerical range, the appearance design is more likely to be improved.
The surface glossiness of the first C layer 30 can be measured by the 60-degree mirror surface gloss method described in JIS Z8741: 1997 "Mirror glossiness-measurement method".
The surface glossiness of the second C layer 32 may be the same as or different from the surface glossiness of the first C layer 30.

The average roughness of the center line of the first C layer 30 is preferably 15 μm or less, more preferably 10 μm or less. When the average roughness of the center line of the first C layer 30 is not more than the above upper limit value, the surface glossiness tends to be 60% or more.
The center line average roughness of the first C layer 30 is the center line average roughness described in JIS B0601: 2013 "Geometrical Characteristic Specifications (GPS) of Product-Surface Texture: Contour Curve Method-Terms, Definitions and Surface Texture Parameters". It can be measured by.
The center line average roughness of the second C layer 32 may be the same as or different from the center line average roughness of the first C layer 30.

The thickness t30 of the first C layer 30 is 0.02 to 0.10 mm, preferably 0.025 to 0.08 mm, more preferably 0.025 to 0.05 mm, and 0.025 to 0.035 mm. Is even more preferable. When the thickness t30 is at least the above lower limit value, the concealing property is improved and the appearance design property is likely to be improved. When the thickness t30 is not more than the above upper limit value, the strength of the foam plate 1 can be more easily improved. The thickness t30 is obtained by the same method as the thickness t10 of the A layer 10.
The thickness t32 of the second C layer 32 is the same as the thickness t30 of the first C layer 30. The thickness t32 and the thickness t30 may be the same or different.

The first C layer 30 is provided with an antistatic agent, an antifogging agent, an antiblocking agent, an antioxidant, a light stabilizer, a crystal nucleating agent, a lubricant, a slippery property, and an antiblocking property, if necessary. Various additives such as the above-mentioned surfactants and fillers may be appropriately added as long as the effects of the present invention are not impaired.

It is preferable that the first C layer 30 is heat-sealed by sandwiching an adhesive film having adhesiveness between the first B layer 20 and the first C layer 30. Alternatively, it is preferable to apply an adhesive between the first B layer 20 and the first C layer 30 to bond the two.

In the present embodiment, a first adhesive layer (not shown) composed of an adhesive is provided between the first B layer 20 and the first C layer 30. The adhesive constituting the first adhesive layer may be any adhesive capable of adhering the first B layer 20 and the first C layer 30, and is a known adhesive usually used for a resin film. Can be used. Examples of the adhesive constituting the first adhesive layer include a thermosetting resin adhesive, an elastomer adhesive, an emulsion adhesive, a hot melt adhesive, and the like, and the thermosetting resin has excellent durability. Adhesives such as hot melt adhesives and hot melt adhesives with less environmental load are preferable.
Examples of the thermosetting resin-based adhesive include a two-component reaction type urethane-based adhesive (for example, manufactured by Toyo Morton Co., Ltd., product number: TM329).
Examples of the hot melt adhesive include polyolefin hot melt adhesives, polyester hot melt adhesives and the like. Examples of the polyolefin-based hot melt adhesive include the trade name "X-2200" (manufactured by Kurabo Industries Ltd.) and the like. Examples of the polyester-based hot melt adhesive include the trade name "PES-111EE" (manufactured by Toagosei Co., Ltd.) and the like.
One type of hot melt adhesive may be used alone, or two or more types may be used in combination.

In the present embodiment, a second adhesive layer (not shown) composed of an adhesive is provided between the second B layer 22 and the second C layer 32. The second adhesive layer is similar to the first adhesive layer. The second adhesive layer may be the same as or different from the first adhesive layer.

The thickness of the first adhesive layer is preferably 10 to 50 μm, more preferably 20 to 40 μm. When the thickness of the first adhesive layer is at least the above lower limit value, the first B layer 20 and the first C layer 30 can be sufficiently easily adhered. If it is equal to or less than the above upper limit value, the amount of heat applied during bonding can be suppressed to a low level, so that the dimensional change can be reduced and the bonding process can be stabilized.
The thickness of the second adhesive layer may be the same as or different from the thickness of the first adhesive layer.

The total thickness T1 of the foam plate 1 is preferably 2.0 to 7.0 mm, more preferably 2.1 to 6.7 mm, further preferably 2.7 to 6.2 mm, and 3.2 to 5.5 mm. Is particularly preferable. When the thickness T1 is at least the above lower limit value, the strength of the foam plate 1 can be more easily improved. When the thickness T1 is not more than the above upper limit value, the thermoformability is likely to be improved.

The foam plate 1 may be further laminated with a printing film on the surface resin layer. As the printing film, a polyolefin-based resin film that can be laminated on the first C layer 30, for example, a polypropylene-based resin film is suitable. The printing film may be adhered to the first C layer 30 via a binder resin, and as the binder resin, for example, a polyester resin film or a polystyrene resin film can be used.
The printing film may be laminated on the second C layer 32.

The method for producing the resin laminated foam plate 1 is not particularly limited, and a known method for producing a resin laminated foam plate or a method for producing a thermoformed laminated sheet described in Patent Document 1 can be used.
The foam plate 1 can be manufactured by, for example, the following method.
In a plurality of extruders, the material resins of the A layer 10, the first B layer 20, the second B layer 22, the first C layer 30 and the second C layer 32 are melted from a die for coextrusion. It can be manufactured by coextrusion foaming. In the material resin, the foaming agent is kneaded with the resin in the extruder for forming the A layer 10.
In addition, the method is not limited to the coextrusion foaming method, and a method may be used in which each layer is extruded separately and then laminated and integrated by heat laminating and extrusion laminating. Alternatively, a method may be used in which the first B layer 20 and the first C layer 30 are laminated in advance, and the first B layer 20 and the first C layer 30 are laminated in advance, and the first layer B 20 and the first C layer 30 are superposed on the separately produced A layer 10 and laminated and integrated by thermal laminating.

The resin laminated foam plate of the present invention is not limited to the foam plate 1 described above. For example, the resin laminated foam plate of the present invention may have an embodiment in which the second C layer 32 is not provided on the second B layer 22. The resin laminated foam plate of the present invention may be an embodiment in which the first B layer 20 and the first C layer 30 are directly heat-sealed without passing through the first adhesive layer. From the viewpoint of further improving the strength and appearance design of the foam plate, the foam plate preferably includes both the first C layer 30 and the second C layer 32.
Further, the resin laminated foam plate of the present invention may be an embodiment in which the first C layer 30 is not provided on the first B layer 20. The resin laminated foam plate of the present invention may be an embodiment in which the second B layer 22 and the second C layer 32 are directly heat-sealed without passing through the second adhesive layer.

In the resin laminated foam plate of the present invention, the first C layer 30 may be provided on the second B layer 22. In the resin laminated foam plate of the present invention, the second C layer 32 may be provided on the first B layer 20.

Since the resin laminated foam plate of the present invention has an A layer, it has excellent impact resistance. Further, since the foam plate of the present invention has a B layer containing an inorganic filler, it is more excellent in strength.
In addition, since the foam plate of the present invention has a C layer as a surface resin layer, it is excellent in appearance design, thermoformability and low temperature brittleness.

The thermoformed product of the present invention is obtained by thermoforming the foam plate of the present invention. This thermoforming can be performed by using the same method and apparatus as those for producing various thermoformed products using the thermoplastic resin foam sheet.

The temperature at the time of thermoforming depends on the molding mold, but is preferably 200 to 300 ° C., for example. When the temperature at the time of thermoforming is equal to or higher than the above lower limit value, the foam plate can be easily thermoformed into a desired shape. When the temperature at the time of thermoforming is not more than the above upper limit value, it is easy to maintain the appearance design of the thermoformed product.

The thermoforming time is preferably, for example, 15 to 30 seconds. When the thermoforming time is equal to or longer than the above lower limit value, the foam plate can be easily thermoformed into a desired shape. When the thermoforming temperature is not more than the above upper limit value, it is easy to maintain the appearance design of the thermoformed product.

Since the melting point of the resin constituting the surface resin layer is lower than the melting point of the resin constituting the adjacent B layer, the thermoformed product of the present invention is excellent in low temperature brittleness and superior in strength. In addition, in the thermoformed product of the present invention, the surface resin layer easily extends during thermoforming and is excellent in thermoforming property. Further, the thermoformed product of the present invention is excellent in appearance design because the surface resin layer has smoothness and the surface glossiness is 60% or more.
Since the thermoformed product of the present invention is excellent in thermoforming property, a thermoformed product having a desired shape can be easily produced.

FIG. 2 shows a perspective view of an assembly box according to an embodiment of the present invention.
The assembly box 100 includes a bottom plate 102 and a side plate 101. The side plate 101 is the foam plate 1 of the present invention. The bottom plate 102 is a thermoformed product of the present invention.
The bottom plate 102 is a rectangular shape in a plan view. The bottom plate 102 has ridges 103, ridges 104, and ridges 105. The ridge 104 orbits along the outer edge of the bottom plate 102. The ridge 103 orbits along the ridge 104. The ridge 103 and the ridge 104 form a ridge 105 between them.

The four side plates 101 are joined in a square cylinder shape. The lower ends of the four side plates 101 fit into the recesses 105 of the bottom plate 102.
The assembly box 100 can be easily assembled in this way, and the side plate 101 can be easily removed from the bottom plate 102 after use. The side plates 101 removed from the bottom plate 102 can be easily unbonded one by one, and by stacking these, space can be saved in the storage space. In addition, the side plate 101 can be easily transported and transported.
If the assembly box 100 becomes dirty after use, it can be used repeatedly by cleaning the four side plates 101 and the bottom plate 102, respectively.

The method of joining the four side plates 101 into a square cylinder is not particularly limited, and for example, they may be joined using an adhesive or an adhesive tape, or they may be joined by making cuts in each other. From the viewpoint of easily assembling the assembly box 100 and easily breaking the joint, it is preferable that the four side plates 101 are notched and joined to each other.

Since the surface resin layer of the foam plate 1 of the present invention is excellent in oil resistance and strength, it is preferable that the surface resin layer is configured so as to face the inner surface of the assembly box 100. When the surface resin layer is coated with an antibacterial coat or the like, the product contained in the assembly box 100 is kept clean.
Further, when the surface resin layer is configured to face the outer surface of the assembly box 100, the assembly box 100 is excellent in impact resistance against dropping or the like.
Therefore, it is more preferable that the surface resin layer is provided on both sides of the foam plate 1.
When the printing film is applied to the surface of the side plate 101, the appearance design can be improved by arranging the printing film on the outside of the assembly box 100. Further, the product name, the name of the seller, and the like in the assembly box 100 may be described by the printing film.

The side plate 101 and the bottom plate 102 have an A layer made of a polypropylene resin. In addition, the side plate 101 and the bottom plate 102 have a B layer made of polypropylene-based resin.
Therefore, from the viewpoint of recycling the assembly box 100, it is preferable that the surface resin layers of the side plate 101 and the bottom plate 102 are made of the same polypropylene-based resin as the A layer and the B layer.

The assembly box of the present invention is not limited to the assembly box 100, and a foam plate 1 that is not thermoformed may be applied to the bottom plate 102. As the side plate 101, a thermoformed product obtained by thermoforming the foam plate 1 may be applied. That is, the assembly box of the present invention may be made of a foam plate 1 in which the bottom plate and the side plate are not thermoformed, or the bottom plate and the side plate may be made of a thermoformed product.

The bottom plate 102 of the assembly box of the present invention may be formed with irregularities according to the shape of the product to be accommodated. Further, the bottom plate 102 may be provided with a plurality of recesses, and the partition plate may be arranged in the accommodating portion of the assembly box.

In the assembly box of the present invention, two bottom plates 102 may be used, and one bottom plate 102 may be used as a canopy of the assembly box.
It is also possible to stack two or more assembly boxes in the height direction to save space in the storage space.

The shape of the assembly box of the present invention may be a rectangular parallelepiped or a cube. The shape of the assembly box can be adjusted by appropriately changing the length of cutting the side plate and the bottom plate.
The shape of the assembly box of the present invention is not limited to a rectangular parallelepiped, and may be a pentagonal or hexagonal boat-shaped shape in a plan view, or a tray-shaped shape in which the height of the side plate is lowered.
In the assembly box of the present invention, the side plate may be thermoformed into a curved surface shape to form a bowl shape having a circular shape in a plan view or an elliptical shape in a plan view.

Since the assembly box of the present invention is composed of a thermoformed product having excellent thermoformability and a foam plate having excellent appearance design, it is excellent in appearance design. In addition, the assembly box of the present invention is more excellent in strength because it is composed of a thermoformed product and a foam plate having excellent strength.
Further, in the assembly box of the present invention, since the side plate and the bottom plate can be easily fitted, it is expected that the efficiency of manufacturing the assembly box will be improved and the cost will be reduced by not using an adhesive.
Further, in the assembly box of the present invention, the side plate and the bottom plate can be easily fitted and the side plates can be easily joined to each other, so that the storage space of the assembly box can be saved. In addition, the side plates and bottom plates may be individually washed for repeated use, or the side plates and bottom plates may be melted and used as a raw material for recycling.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following description.

[Example 1]
As the polypropylene resin for the A layer, the trade name "WB140HMS" (melt tension 23 cN, MFR = 1.7 g / 10 minutes) manufactured by Borealis, 45% by mass, and the trade name "BC6C" manufactured by Nippon Polypro Co., Ltd. as the block PP. A resin component containing 45% by mass and 10% by mass of the trade name "Q-100F" as a polyolefin-based thermoplastic elastomer (TPO) and a ratio of 0.2 parts by mass to 100 parts by mass of the resin component are obtained. A second extrusion with a diameter of 115 mm is applied to the tip of a first extruder with a diameter of 90 mm using a resin containing a baking soda-citrate foaming agent (master batch manufactured by Dainichi Seika Co., Ltd., trade name "Finecell Master PO410K"). We prepared a tandem extruder that connects the machines. Then, a polypropylene resin is supplied to the first extruder of this tandem type extruder, melt-kneaded at about 200 to 210 ° C., and then butane (normal butane / isobutane (mass)) is used as a foaming agent in the first extruder. Ratio) 65/35) 3.0 parts by mass is press-fitted and further melt-kneaded, cooled to about 175 ° C., and supplied to an annular die connected to the tip of the second extruder to form a cylindrical shape. It was extruded and foamed at an extrusion rate of 150 kg / hour.
After cooling the obtained cylindrical foam by blowing air on its inner surface, the inner surface is solidified along the cooling mandrel plug, and the outer surface is also cooled and solidified by blowing cooling air on the plug. , The cylindrical foam was continuously cut and cut open between the inner and outer peripheral surfaces in the extrusion direction (MD direction), and thus wound into a roll as a continuous sheet. As a result, a polypropylene-based resin foam sheet (layer A) having a basis weight of 560 g / m ^{2 and a thickness of 5.0 mm could be stably obtained.}

The obtained foamed sheet contains 43% by mass of BC6C (block PP, manufactured by Japan Polypropylene Corporation) 57% by mass (MFR = 2.5) and 70% by mass of inorganic filler 70P (manufactured by Nitto Flour Chemical Co., Ltd.) as the B layer. %, And the inorganic filler was prepared in an amount of 30% by mass. This polypropylene resin was supplied to each of the two extruders. A sheet in a molten state immediately after being extruded from a T-die attached to the tip of the first extruder was laminated on one surface of the polypropylene-based resin foam sheet to be heat-sealed and integrated. At the same time, the molten sheet immediately after being extruded from the T-die attached to the tip of the second extruder is laminated on the other surface of the polypropylene-based resin foam sheet to be heat-sealed and integrated, and polypropylene-based on both sides. A laminated sheet was obtained by laminating the resin layer (B layer). The obtained laminated sheet had a basis weight of 860 g / m ² and a thickness of 5.2 mm. The extrusion conditions of the two second extruders were the same.
Both T-dies attached to the tips of the two second extruders have the temperature of the remaining part other than both ends so that the temperature of both ends in the width direction (TD direction) in the resin flow path is 240 ° C. The temperature was adjusted to 260 ° C.

A C layer (CPP film, manufactured by Towa Kako Co., Ltd.) of 30 μm was laminated on one surface of the laminated sheet by a hot roll via a hot melt adhesive film (trade name “X-2200” manufactured by Kurabo Industries Ltd.) having a thickness of 20 μm. ..
Through the above steps, a foam plate having the layer structure shown in Table 1 was obtained. The B layer shown in Table 1 represents the first B layer, and the second B layer has the same physical characteristics. The C layer shown in Table 1 represents the first C layer, and the second C layer has the same physical characteristics.

[Examples 2 to 5, Comparative Examples 1 to 9]
A foam plate was obtained by appropriately adjusting the press-fitting amount, the discharging amount, and the taking-up speed of the foaming agent under the same conditions as in Example 1 so as to have the layer structure having the physical properties shown in Table 1.
In Example 3, E111G (Homo PP, manufactured by Prime Polymer Co., Ltd., MFR = 0.5, melting point 163 ° C.) was used as the resin component of the B layer.
In Comparative Examples 3, 5, 7, and 8, in order to obtain a predetermined thickness, a foam plate in which the foaming ratio of the A layer was suppressed was obtained by setting the press-fitting amount of the foaming agent to 1.5 to 2.5 parts by mass. .. In addition, Examples 2 to 4 are reference examples.

[Comparative Example 10]
As the polypropylene-based resin for the A layer, "WB140HMS" was blended in an amount of 27% by mass, "BC6C" was blended in a proportion of 25% by mass, "Q-100F" was blended in a proportion of 5% by mass, and "Tarpet 70P" was blended in a proportion of 43% by mass. The amount of the foaming agent press-fitted was 1.3 parts by mass, and the mixture was cooled to 185 ° C., and a foam plate was obtained in the same manner as in Example 1 under other conditions.

Various physical property tests were carried out using the obtained foam plates of each example. The evaluation method is shown below, and the evaluation results are shown in Table 2.

[Bending strength]
Using a test piece cut out to a size of width 50 mm × length 150 mm × thickness (thickness of each example), the bending strength in the MD direction and the TD direction was measured under the following conditions.
(Test conditions)
Measuring device: Tensilon universal testing machine RTG-1310 (manufactured by A & G).
n number: 3.
Test speed: 50 mm / min.
Distance between fulcrums: 100 mm.
Tip jig: Pressurized wedge 5R.
Support stand: 2.5R.
The arithmetic mean value of the obtained bending strength is taken as the bending strength (MPa) in each direction and is shown in Table 2. The larger the bending strength value, the more rigid the foam plate and the better the strength.

[Evaluation of thermoformability]
The obtained foam plates of each example were thermoformed (temperature 260 ° C., time 17 seconds) to produce a thermoformed product as a bottom plate.
The obtained thermoformed product was left to stand for 2 hours in an environment of 23 ± 2 ° C. and a humidity of 50 ± 5% RH. Then, the surface of the thermoformed product was visually confirmed, and the thermoforming property was evaluated according to the following evaluation criteria.
(Evaluation criteria)
◯: The surface film is smooth, does not peel off, and has good thermoformability.
Δ: The film on the surface is smooth, but it is inferior in thermoformability due to peeling and the like.
X: The film on the surface has irregularities and may be peeled off.

[Evaluation of appearance design]
Using the obtained foam plates of each example, the surface glossiness of the surface resin layer was measured according to the 60-degree mirror surface gloss method described in JIS Z8741: 1997 "Mirror surface gloss-measurement method".
The appearance design was evaluated using a gloss checker IG320 (manufactured by HORIBA, Ltd.) according to the following evaluation criteria. The results are shown in Tables 1 and 2.
(Evaluation criteria)
◯: Surface gloss is 60% or more.
X: Surface gloss is less than 60%.

[Evaluation of low temperature brittleness]
Using the thermoformed products obtained in each example as the bottom plate and the foam plates of the same Example and the same Comparative Example as side plates, a square tray-shaped molded product having a length of 160 mm, a width of 100 mm, and a height of 35 mm was produced.
At this time, a molded product was produced so that the surface resin layers of the bottom plate and all the side plates faced the outer surface.
200 g of water was added to the obtained molded product, and the product was allowed to stand in a freezer at −20 ° C. for 24 hours to freeze the water. This molded product was dropped from a height of 500 mm, the change in the shape of the molded product was visually confirmed, and the low temperature brittleness was evaluated according to the following evaluation criteria. The results are shown in Table 2. The low temperature brittleness is an index indicating the strength of a molded product assuming an assembly box.
(Evaluation criteria)
◯: Although there is a dent, the shape of the molded product is maintained.
Δ: Cracks occur.
X: Cracks (a state in which voids are present in the cracks) occur, or the shape of the molded product is deformed.

In Examples 1 to 5 to which the present invention was applied, the evaluations of thermoforming property, appearance design property, and low temperature brittleness were all "◯". On the other hand, in Comparative Example 1 in which a resin having a high melting point was used for the layer (C), the thermoformability and the appearance design were “x”. In Comparative Example 2 in which the content of the inorganic filler was high, the thermoformability was “x”. In Comparative Examples 3, 5 and 8 in which the thickness of the A layer was small, the low temperature brittleness was “x” and the strength was inferior. In Comparative Example 4 in which the B layer did not contain an inorganic filler, the thermoformability and low-temperature brittleness were “Δ”, and the strength was inferior. In Comparative Example 6 in which a resin having a high melting point was used for the C layer, the thermoformability was “x”. In Comparative Examples 7 and 10 in which the closed cell ratio of the A layer was less than 70%, the thermoformability and the low temperature brittleness were "Δ", and the strength was inferior. In Comparative Example 9 using a resin film having a low surface gloss, the appearance design was “x”.

From these results, it was found that the resin laminated foam plate of the present invention is excellent in thermoforming property and appearance design property, and is also excellent in strength.

1 Resin laminated foam plate 10 A layer 20 First B layer 22 Second B layer 30 First C layer 32 Second C layer 100 Assembly box 101 Side plate 102 Bottom plate 103, 104 Convex 105 Concave

Claims (5)

A foamed resin layer (A) of a polypropylene resin, a non-foamed resin layer (B) of a polypropylene resin provided on both sides thereof, and an unstretched polypropylene provided on at least one of the non-foamed resin layers (B). A resin laminated foam plate provided with a non-foamed resin layer (C) of a film.
The foamed resin layer (A) has a closed cell ratio of 70% or more, a thickness of 2.0 to 6.0 mm, a basis weight of 560 to 700 g / m ² , and is substantially an inorganic filler. Not contained,
The non-foaming resin layer (B) contains 5 to 40% by mass of the inorganic filler with respect to the total mass of the non-foaming resin layer (B).
The melting point of the resin of the non-foaming resin layer (C) is lower than the melting point of the resin of the foamed resin layer (A), and the non-foaming resin layer (B) adjacent to the non-foaming resin layer (C). Lower than the melting point of the resin
The non-foamed resin layer (C) is a resin laminated foam plate having a surface glossiness of 60% or more and a thickness of 0.02 to 0.10 mm. The first aspect of the present invention, wherein the melt mass flow rate (MFR) of the resin of the foamed resin layer (A) and the resin of the non-foamed resin layer (B) at 230 ° C. and 0.23 MPa is 5.0 g / 10 min or less. Resin laminated foam board. The resin laminated foam plate according to claim 1 or 2, wherein the foamed resin layer (A) has a density of 100 to 350 kg / m ³ , and the foamed resin layer (A) has an average cell diameter of 20 to 200 μm. .. A thermoformed product obtained by thermoforming the resin laminated foam plate according to any one of claims 1 to 3. An assembly box in which the thermoformed product according to claim 4 is used as a bottom plate, and the resin laminated foam plate according to any one of claims 1 to 3 is used as a side plate.

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