JP5664184B2 - Resin composition for foam molding, resin sheet for foam molding, and foam molding - Google Patents

Description

  The present invention relates to a polyester-based resin composition for foam molded article, a resin sheet for foam molded article, and a foam molded article. More specifically, the foam molding can provide a polyester resin foam having high light reflectivity, excellent lightness, and suitable for use as a light reflecting member for a liquid crystal display device backlight or a light reflecting member for an electric bulletin board. The present invention relates to a body resin composition, a resin sheet for foam molding, and the foam molding.

  Since the liquid crystal display device does not emit light by itself, a separate backlight unit is required. The backlight unit is a component that plays an important role in the brightness and appearance of the screen. In particular, it plays an important role in luminance increase / decrease. In addition, the reflecting member that reflects light is disposed around the lamp in the backlight unit of the liquid crystal display device, and thus plays a considerably important role.

  As such a reflecting member, for example, (i) a light reflecting member having a three-layer structure including an intermediate layer made of a polyester film containing micro bubbles formed by mixing foaming chemicals and an outermost layer containing calcium carbonate (Iii) a light-reflecting member having a three-layer structure comprising an intermediate layer made of foam and an outermost layer containing barium sulfate to increase the reflection efficiency; (iii) formed by batch foaming with an inert gas; There is known a light reflecting member containing 2 or more micro bubbles. Further, as a general reflecting member, a member having a structure capable of regularly reflecting light by coating silver is known.

  However, the reflection member (light reflection member) is the light reflection member obtained in (i), and the light reflection member obtained in (ii) has a large micro-bubble and low reflection characteristics (for example, Patent Document 1). Has a very low expansion ratio and low reflection characteristics (for example, Patent Document 2), and the light reflection member obtained in (iii) is excellent in reflection characteristics, but takes a crystallization time due to impregnation with a non-reactive gas ( For example, it has the disadvantages of Patent Document 3 and Patent Document 4).

JP 2006-195001 A JP 2007-261260 A Japanese Patent Laid-Open No. 05-230259 JP 2009-209171 A

  The objective of this invention is providing the resin composition for foaming moldings, the resin sheet for foaming moldings, and a foaming molding which can provide the light reflection member excellent in light reflectivity and lightness. As a result of diligent studies to solve the above problems, the present inventors used a polyester resin foam obtained by foam molding a resin composition containing two or more polyester resins and a polymer having a polar group as a light reflecting layer. It was found that a light reflecting member excellent in crystallization time by impregnation with light reflectivity, light weight and non-reactive gas can be obtained by including it, and the present invention has been completed.

That is, this invention consists of the following structures.
1. A resin composition for impregnating with a non-reactive gas and then heating to form a foamed molded product, mainly comprising a polyester resin mainly composed of components derived from terephthalic acid and ethylene glycol, and other polar groups. A resin composition for foamed molded articles, comprising: a polymer having a polyester resin having a difference in melting point of 10 ° C. or more or a glass transition temperature of 10 ° C. or more lower than that of a main polyester resin.
2. The polyester resin having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin is a polyester resin mainly composed of the same polycarboxylic acid and / or polyhydric alcohol as the main polyester resin. The resin composition for foam molded articles according to the first aspect.
3. The polymer having a polar group described in the first is a polyester resin, and a polyester resin having a melting point difference of 10 ° C. or higher or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin. The resin composition for foamed molded products according to the first aspect, which comprises the same polyvalent carboxylic acid and / or polyhydric alcohol as the polyester-based resin.
4). The polymer having a polar group described in the first is an olefin resin, and a polyester resin having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin is glutaric acid, Adipic acid, sebacic acid, azelaic acid, oxalic acid, succinic acid and the like, or aliphatic dicarboxylic acid usually called dimer acid, and / or ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9- Nonanediol, aliphatic diols such as 1,10-decanediol, Alicyclic diols such as rhohexanedimethanol and 1,4-cyclohexanediethanol, aliphatic polyhydric alcohols such as trimethylolpropane and pentaerythritol, polyalkylene ethers such as polyethylene oxide glycol, polypropylene oxide glycol and polytetramethylene oxide glycol The resin composition for foamed molded products according to the first aspect, comprising at least one or more of glycol, a mixture thereof and a copolymerized polyether glycol obtained by copolymerizing these ether components.
5. The resin composition for foam molded articles according to the first aspect, wherein the main polyester resin is 60% by mass or more.
6). The resin composition for foam molded articles according to the first aspect, wherein the polymer having a polar group is 0.1% by mass or more.
7). The resin composition for a foam molded article according to the first aspect, wherein a polyester resin having a melting point difference of 10 ° C. or higher or a glass transition temperature difference of 10 ° C. or higher is 0.1 mass% or higher than the main polyester resin .
8). The resin composition for a foam molded article according to the first aspect, wherein the time required for the crystallinity to exceed 25% is less than 42 hours when the crystallinity after impregnation with the non-reactive gas is evaluated.
(However, the degree of crystallinity is obtained by cutting a sample piece of 35 mm length × 45 mm width × 0.6 mm thickness from a resin sheet and supercritical fluid processing test equipment (model: HV1-SC, Nisaka Manufacturing Co., Ltd.) And exposed to CO ₂ gas at 25 ° C. and 6 MPa for a predetermined time, the sample piece was taken out of the supercritical fluid processing test apparatus and air-dried at 23 ° C. × 50% RH × 48 hours. The sample piece after air drying was set in a differential scanning calorimeter (EXSTAR6000, manufactured by SII Nano Technology Co., Ltd.), and the amount of heat based on crystallization and melting of the sample piece was measured while raising the temperature at 10 ° C./min. And calculated based on the following formula.
Crystallinity (%) = (A−B) / C
A: Calorie based on melting (J / g)
B: Heat quantity based on crystallization (J / g)
C: Heat of fusion of 100% crystallized PET (117.6 (J / g))
9. A resin sheet for foam-molded body, which is obtained from the resin composition for foam-molded body according to the first aspect.
10. A foam molded article obtained from the resin sheet for foam molded article according to the ninth aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the light reflection member excellent in the crystallization time by impregnation of light reflectivity, lightweight property, and non-reactive gas can be provided.

(Resin composition)
In the present application, the resin composition of the present invention is used for a polyester resin foam (foam) useful as a light reflecting layer in a light reflecting member, and contains at least a polyester resin. It is the composition which becomes.
That is, a polyester resin mainly containing components derived from terephthalic acid and ethylene glycol is used, and a polymer having a polar group and a difference in melting point of 10 ° C. or more than that of the main polyester resin or a glass transition temperature of 10 It is a resin composition for foamed molded articles characterized by containing a polyester-based resin having a temperature lower than 0 ° C., and may further contain powder particles, additives and the like as required.
The main polyester resin is preferably polyethylene terephthalate. The term “polyethylene terephthalate” as used herein means that, in addition to terephthalic acid as a carboxylic acid component, about 8 mol or less of isophthalic acid is used, and 8 mol% in addition to ethylene glycol as a glycol component Also included are those comprising less than or equal to diethylene glycol. In the case where isophthalic acid is included in addition to terephthalic acid as the carboxylic acid component, or about 8 mol% or less of diethylene glycol is included in addition to ethylene glycol as the glycol component, isophthalic acid and / or diethylene glycol is included in an amount of about 1 mol% or more. Is preferred. In addition, an unfoamed resin molded body can be obtained by molding the resin composition.

In particular, when the resin composition contains a polymer having a polar group and a polyester resin having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin, the resin composition does not react. By containing a reactive gas, a highly foamed and high-density foamed molded article with high reflectivity can be obtained.
The larger the number of polar groups per repeating unit than the main polyester resin is, the better. The difference in melting point is preferably 15 ° C. or higher, more preferably 20 ° C. or higher. However, if the difference between the melting points is too large, the thermal decomposition of the polyester resin corresponding to the low temperature side of the melting point difference or the melt flow property difference between the polyester resins may become significant. It is preferable that it is 150 degrees C or less.

By containing a polymer having a polar group and a polyester resin having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin, high foaming with high reflectivity and high density foaming The reason why the molded body is obtained is estimated as follows.
When the polyester resin is crystallized by containing a non-reactive gas in the polyester resin, the difference between the melting point of the polymer having a polar group with respect to the main polyester resin dispersed in the polyester resin and the main polyester resin is 10 A polyester resin having a temperature difference of 10 ° C. or higher or a glass transition temperature difference of 10 ° C. or higher is a starting point for crystal nucleation, produces a microcrystal, or a non-reactive gas is a polymer having a polar group with respect to the polyester resin The polyester resin has a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more which is unevenly distributed or impregnated or contained in a high concentration, or the origin of bubble nucleation in the foaming process, Alternatively, a polymer having a polar group with respect to the polyester resin in the polyester resin, A polyester resin having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more is finely foamed by finely dispersing or compatibilizing the dispersion diameter of the polyester resin from a micron order to a submicron or less. It is thought that it is due to exerting such effects.
As a result, it is possible to obtain a foamed molded article having a high reflectance and containing uniform fine pores having an average bubble diameter of 30 μm or less and further 10 μm or less.

(Characteristics of polyester resin)
The intrinsic viscosity of the polyester resin used in the present invention is 0.5 dl / g or more (preferably 0.6 dl / g or more, more preferably 0.7 dl / g or more, more preferably 0, as measured by the method described later. 0.8 dl / g or more). Since the polyester resin used in the present invention is a resin composition for foamed molded articles, mechanical properties and impact strength may be lowered when the intrinsic viscosity is less than 0.5 dl / g.

(Polyester resin content)
The resin composition for foam molded articles according to the present invention preferably contains 60% by mass (more preferably 70% by mass or more, and still more preferably 80% by mass or more) of the main polyester resin. When the content rate of the polyester resin is less than 60% by mass, the heat resistance and rigidity of the foamed molded article obtained using this polyester resin are remarkably unfavorable.

  Moreover, it is also preferable that the content rate with respect to the resin composition of the polyester-type resin whose melting | fusing point is 10 degreeC or more lower than the polymer which has a polar group, and main polyester resin is 0.1 mass% or more. More preferably, it is 0.5 mass% or more, Most preferably, it is 0.7 mass% or more. The content of the polyester-based resin with respect to the resin composition is 0.1% by mass or more with a difference in melting point of 10 ° C. or more than the polymer having a polar group and the main polyester resin or a difference in glass transition temperature of 10 ° C. or more. Thus, when the polyester resin is crystallized, the crystallization speed is further increased. However, the content of the polyester-based resin in the resin composition having a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the polymer having the polar group and the main polyester resin is high in heat resistance. Or less than 40% by weight, and more preferably 30% by weight or less.

(Method for producing polyester resin and polyester resin having polar group)
The production method of the polyester resin used in the present invention is not particularly limited. For example, the polyester resin can be produced by using terephthalic acid and ethylene glycol as main components through esterification reaction, melt polycondensation, and solid phase polymerization. it can. Further, instead of terephthalic acid, an ester exchange reaction may be performed using an ester such as dimethyl terephthalate.

<Esterification reaction>
The esterification reaction of the raw material component mainly composed of terephthalic acid and ethylene glycol can be carried out by stirring the raw material component at 100 to 300 ° C. under normal pressure to pressure. At this time, the raw material components may be stirred in the presence of nitrogen gas.

  As a raw material component used when performing esterification reaction, other components (polyhydric carboxylic acid, polyhydric alcohol) may be contained in addition to the terephthalic acid and ethylene glycol.

  For example, polyvalent carboxylic acids other than terephthalic acid include isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, 5-sodium sulfoisophthalic acid, 4,4′-diphenyldicarboxylic acid, diphenylsulfodicarboxylic acid. Aromatic dicarboxylic acids such as acids, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, succinic acid, etc., and aliphatic dicarboxylic acids, trimellitic acid, pyromellitic acid and their commonly called dimer acid Aromatic polyvalent carboxylic acids such as acid anhydrides may be mentioned. In the present invention, the polyvalent carboxylic acid component is used so that the main polyester resin has a polar group and / or the difference in melting point is 10 ° C. or more or the difference in glass transition temperature is 10 ° C. or more. It is preferable to be used.

  In addition, as polyhydric alcohols other than ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, Aliphatic diols such as 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol , Alicyclic diols such as 1,4-cyclohexanediethanol, aliphatic polyhydric alcohols such as trimethylolpropane and pentaerythritol, polyalcohols such as polyethylene oxide glycol, polypropylene oxide glycol and polytetramethylene oxide glycol Furthermore ether glycol and mixtures thereof copolymerized polyether glycol obtained by copolymerization of these ether components and the like. In the present invention, a polyhydric alcohol is used so as to have a polar group with respect to the main polyester resin and / or such that the difference in melting point is 10 ° C. or more or the difference in glass transition temperature is 10 ° C. or more. It is preferable.

<Melting polycondensation>
The melt polycondensation can be performed by adding a polycondensation catalyst to the reaction product obtained by the esterification reaction and stirring at 100 ° C. to 300 ° C. and 13.3 Pa to 3990 Pa.

  Various conventional catalysts can be used as the polycondensation catalyst, such as titanium-based catalysts (titanium tetrabutoxide, etc.), antimony-based catalysts (antimony trioxide, antimony acetate, etc.), germanium-based catalysts (germanium dioxide, etc.), cobalt-based catalysts. Examples thereof include catalysts (such as cobalt acetate), tin-based catalysts (such as monobutylhydroxytin oxide), manganese-based catalysts (such as manganese acetate), and aluminum-based catalysts (such as basic aluminum acetate). These polycondensation catalysts may be used alone or in combination of two or more.

<Solid-state polymerization>
In the solid-phase polymerization, a polyester resin prepolymer obtained by melt polycondensation is cut while being cooled with water or the like to obtain chips having an average particle size of 1.5 mm to 5 mm, and then subjected to inert gas flow or reduced pressure. The heating can be carried out by heating at a temperature below the melting point of the prepolymer, preferably for 1 to 30 hours.

  Prior to solid phase polymerization, precrystallization may be performed at a temperature lower than the temperature at which solid phase polymerization is performed. Thereby, solid phase polymerization can proceed more efficiently. This precrystallization step is performed, for example, by heating a prepolymer chip at 50 to 240 ° C. for 1 to 24 hours in an inert gas, under reduced pressure, or in an atmosphere of steam or a steam-containing inert gas. be able to.

  After cutting the polyester resin prepolymer into chips, fine powder contained in the prepolymer chips by passing through a sieve or by passing a cyclone air filter if the chips are air-fed It is preferable to remove the sheet-like material. Thereby, a long polyester resin sheet having a uniform composition can be obtained.

(Olefin resin having a polar group with respect to the polyester resin)
The resin composition for a foam molded article of the present invention may be an olefin resin having a polar group with respect to the polyester resin in addition to the polyester resin having the polar group. Even by foaming a resin sheet obtained from a polyester resin composition comprising an olefin resin having a polar group with respect to the polyester resin, it contains uniform fine pores having an average cell diameter of 50 μm or less inside. A foamed molded product having a high reflectance can be obtained.

  The average bubble diameter is obtained by taking a SEM photograph of the cross section of the foam molded body, and calculating the diameter when the observed bubble is approximated to a sphere for any 30 bubbles included in the constant cross-sectional area of the foam layer. It can be obtained by averaging.

  Examples of the olefin resin having a polar group with respect to the polyester resin used in the present invention include general-purpose low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and polypropylene (PP). , Polymethylpentene (PMP), ethylene-based copolymer, styrene-based copolymer, etc., specifically, ethylene vinyl acetate (EVA), ethylene methyl methacrylate (EMMA), ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate maleic anhydride (E-EA-MAH), ethylene acrylic acid (EAA), ethylene methacrylic acid (EMAA), ionomer (ethylene methacrylate metal cross-linked), MAH- G-Polio Fins (PE or PP grafted with maleic anhydride), ethylene glycidyl methacrylate (E-GMA), ethylene glycidyl methacrylate vinyl acetate (E-GMA-VA), ethylene glycidyl methacrylate methyl acrylate (E-GMA-MA) ), Styrene-butadiene-styrene copolymer (SBS), styrene-ethylene / butylene-styrene copolymer (SEBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / propylene copolymer (SEP) ), Styrene-ethylene / butylene-ethylene copolymer (SEBC), hydrogenated styrene / butadiene copolymer (HSBR), etc., amino groups, epoxy groups, carboxyl groups (acid anhydrides, carboxyls in the form of metal salts) Group), hydroxyl , An aldehyde group, a carbonyl group, a sulfo group, a nitro group, a halogen group, oxazoline group, isocyanate group, it is preferable to have a functional group such as a thiol group. Among these, SEBS and SEBC having a functional group are more preferable.

  For example, when the functional group is an epoxy group, the functional group is introduced into the styrene-based copolymer by partially epoxidizing the diene component or graft-modifying an epoxy-containing compound such as glycidyl methacrylate. be able to.

  The content of the olefin-based resin having a polar group with respect to the polyester resin in the resin composition of the present invention is 0.1% by mass or more (more preferably 0.5% by mass) in 100% by mass of the resin composition for foam molded articles. % Or more, more preferably 0.7% by mass or more) is preferable, and 40% by mass or less (more preferably 20% by mass or less, further preferably 5% by mass or less) is preferable. When the content is less than 0.1% by mass, the effect of obtaining a high-foamed and high-density foamed molding is reduced. Moreover, when it exceeds 40 mass%, since the content rate of the polyester resin in a resin composition falls as a result, the heat resistance of the foaming molding obtained, rigidity, and intensity | strength may fall, and it is not so much. It is not preferable.

(Powder particles)
In the present invention, the polyester resin foam used for forming the light reflecting member may further contain powder particles. That is, the resin composition used for the foam molding of the polyester resin foam can also contain a polyester resin and powder particles. The powder particles can function as a foam nucleating agent during foam molding. Therefore, the polyester resin foam of a favorable foaming state can be obtained by mix | blending powder particles. If powder particles are used in the resin composition and a supercritical fluid is used as a high-pressure gas that is a foaming agent used for foaming the polyester resin, a polyester resin foam having particularly fine and uniform cells can be obtained. Can do.

  Examples of such powder particles include clays such as talc, silica, alumina, zeolite, calcium carbonate, magnesium carbonate, barium sulfate, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, mica, montmorillonite, and carbon particles. Glass fiber, carbon tube, etc. can be used. The powder particles can be used alone or in combination of two or more.

  Although it does not restrict | limit especially as a content rate of a powder particle, For example, 0.1-30 mass% (preferably 0.5-20 mass%, More preferably 1 with respect to 100 mass% of polyester resins in a resin composition. 0.0 to 15% by mass). When the content of the powder particles is less than 0.1% by mass with respect to 100% by mass of the polyester resin, it becomes difficult to obtain a uniform foam. On the other hand, when the content exceeds 30% by mass, the resin composition While the viscosity increases remarkably, outgassing occurs during foaming, which may impair foaming characteristics.

  Although it does not restrict | limit especially as an average particle diameter of a powder particle, For example, it is about 0.1-10 micrometers (preferably 0.5-5 micrometers). If the average particle size of the powder particles is less than 0.1 μm, it may not function sufficiently as a nucleating agent, and if the average particle size exceeds 10 μm, it may cause outgassing during foam molding.

(Melting point and glass transition temperature of polyester resin)
DSC measurement was performed according to “Plastic Transition Temperature Measurement Method” described in JIS K7121. About 10 mg of the polyester resin was sealed in an aluminum pan, melted at 300 ° C. for 3 minutes, and quenched with liquid nitrogen. A differential scanning calorimeter (EXSTAR6000, manufactured by SII NanoTechnology Inc., hereinafter may be simply referred to as “DSC”) was used as a measuring instrument, and the measurement was performed in a dry nitrogen atmosphere. After heating at a rate of 10 ° C./min to determine the midpoint glass transition temperature, the melting peak temperature (melting point) was determined.

(Crystallinity)
The resin composition for foam molding of the present invention has a CO ₂ exposure time of 42 hours or less (more preferably, crystallization) required for the crystallinity to exceed 25% when the crystallinity is evaluated by the following method. The CO ₂ exposure time required for the degree to exceed 25% is preferably within 36 hours). Thereby, since it becomes possible to make the resin sheet obtained from the resin composition of this invention into a foaming molding rapidly, it contributes to mass production of a foaming molding and can further suppress manufacturing cost.

(Crystallinity evaluation method)
From a resin sheet obtained from the resin composition for a foam molded article of the present invention, a sample piece having a size of 35 mm in length, 45 mm in width, and 0.6 mm in thickness was cut out, and a supercritical fluid processing test apparatus (model: HV1-SC) was obtained. , Manufactured by Nisaka Seisakusho Co., Ltd.) and exposed to CO ₂ gas at 25 ° C. and 6 MPa for a predetermined time. H. X Air-dried for 48 hours. Next, the air-dried sample piece is set in a differential scanning calorimeter (EXSTAR6000, manufactured by SII Nano Technology Co., Ltd.), and the amount of heat based on crystallization and melting of the sample piece is increased while the temperature is raised at 10 ° C./min. The crystallinity was calculated based on the following formula.
Crystallinity (%) = (A−B) / C
A: Calorie based on melting (J / g)
B: Heat quantity based on crystallization (J / g)
C: Heat of fusion of 100% crystallized PET (117.6 (J / g))

(Additive)
In the resin composition for a foam molded article of the present invention, various additives (for example, an antioxidant, an antistatic agent, an ultraviolet ray preventive agent, a range of additives that do not affect the properties of the foam molded article obtained by using the resin composition) Light stabilizers, fluorescent brighteners, colorants, antibacterial agents, compatibilizers, lubricants, reinforcing agents, flame retardants, etc.) may be blended.

  In particular, an alkali metal (such as lithium acetate), an alkaline earth metal (such as magnesium acetate), or a phosphorus-containing compound (such as trimethyl phosphate) is preferably added as an additive. By blending an alkali metal or an alkaline earth metal, the resin sheet is easily adhered to the roll when the resin sheet is obtained from the resin composition by a casting method based on the electrostatic adhesion system. Moreover, the resin composition excellent in thermal stability can be obtained by mix | blending a phosphorus containing compound.

(Foam molding)
Although it does not specifically limit as a method of obtaining a foaming molding using said resin composition for foaming moldings, For example, the following method is mentioned.

  That is, first, two or more kinds of polyester resin chips, a polymer having a polar group (chip), and various additives such as an antistatic agent, if necessary, a dryer such as a hopper dryer or a paddle dryer, or It dries using a vacuum dryer and extrudes into a film at a temperature of 150 to 300 ° C. using an extruder to produce a polyester resin sheet (unstretched). Alternatively, two or more kinds of polyester resin chips that are undried, a polymer having a polar group (chip), and various additives such as an antistatic agent as necessary while removing moisture in a vented extruder. Similarly, it is extruded into a film shape to produce a polyester resin sheet (unstretched). When extruding, any existing method such as a T-die method or a tubular method may be adopted.

  After extrusion, quench with a casting roll. At that time, an electrode may be disposed between the extruder and the casting roll, and a voltage may be applied between the electrode and the casting roll to electrostatically adhere the sheet to the roll.

  Next, the polyester resin sheet and the separator are overlapped and wound to form a roll, and this roll is held in a pressurized nonreactive gas atmosphere to impregnate the polyester resin sheet with the nonreactive gas.

  Here, examples of the non-reactive gas that can be used in the present invention include carbon dioxide, helium, nitrogen, argon, and the like, and considering the gas permeability (rate, solubility, critical point) to the resin, carbon dioxide. Is more preferable.

The non-reactive gas permeation treatment time and permeation amount into the polyester resin sheet are appropriately adjusted depending on the type of resin to be foamed, the type of non-reactive gas, the permeation pressure, and the thickness of the sheet. The aspect which impregnates the polyester resin sheet with non-reactive gas under 4.0-7.1 MPa is mentioned. Specifically, when the polyester resin sheet of the present invention is impregnated with carbon dioxide, the crystallinity of the polyester resin sheet is 25% in a chamber filled with CO ₂ gas at 25 ° C. and 6 MPa. Hold the roll until.

  In addition, you may perform the impregnation of the non-reactive gas to a polyester resin sheet in a supercritical state.

  Thereafter, the polyester resin sheet impregnated with the non-reactive gas is heated to a temperature equal to or higher than the softening temperature of the polyester resin and foamed under normal pressure. Specifically, in the present invention, a polyester resin sheet impregnated with a non-reactive gas is heated at 240 ° C. for 1 minute.

The apparent density of the obtained foamed molded product is preferably 100 to 1300 kg / m ³ .

<Application>
The foamed molded article of the present invention is excellent in reflectivity. Specifically, the average total reflectance in the light wavelength region of 400 to 700 nm is 90% or more when measured by the method described later. For this reason, it can be suitably used not only for electric signboards, lighting fixtures, and substrates for liquid crystal display reflectors but also for other applications where high reflectivity is required.

  The foam-molded body is a single-layer body composed only of a foam layer composed of a polyester foam composed of two or more polyesters and a polymer resin foam having a polar group, or provided on at least one surface of the foam layer and the foam layer. It is also preferable that the laminate is composed of a non-foamed layer formed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and may be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention. These are all included in the technical scope of the present invention. The measurement / evaluation methods employed in the examples are as follows. In the examples, “parts” means “parts by mass”, and “%” means “% by mass” unless otherwise specified.

(Measurement and evaluation method)
(1) Polyester resin composition The composition of the polyester resin used in the present invention was determined by dissolving 15 mg of a polyester resin sample in CDCl ₃ / CF ₃ COOH (85/15) and measuring H-NMR.

(2) Intrinsic viscosity The intrinsic viscosity IV (measured value) of the polyester resin used in the present invention is determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 mass ratio) mixed solvent. It was.

(3) Crystallinity degree A sample piece having a size of 35 mm in length, 45 mm in width, and 0.6 mm in thickness is cut out from the resin sheet obtained from the resin composition for foamed moldings of the present invention, and a supercritical fluid treatment test apparatus (Model: HV1-SC, manufactured by Nisaka Seisakusho Co., Ltd.) and exposed to CO ₂ gas at 25 ° C. and 6 MPa for a predetermined time, the sample piece is taken out from the supercritical fluid processing test apparatus, and 23 ° C. × 50 % R. H. X Air-dried for 48 hours. Next, the air-dried sample piece is set in a differential scanning calorimeter (EXSTAR6000, manufactured by SII Nano Technology Co., Ltd.), and the amount of heat based on crystallization and melting of the sample piece is increased while the temperature is raised at 10 ° C./min. The crystallinity was calculated based on the following formula.
Crystallinity (%) = (A−B) / C
A: Calorie based on melting (J / g)
B: Heat quantity based on crystallization (J / g)
C: Heat of fusion of 100% crystallized PET (117.6 (J / g))

(4) Total reflectance Using a spectrophotometer (UV-3150, manufactured by Shimadzu Corporation), the reflectance of the foamed molded product in the light wavelength region of 400 to 700 nm is measured, and the reflectance is measured at intervals of 2 nm from the obtained chart. The average value was measured. In Table 1 below, the total reflectance of a white plate obtained by solidifying fine powder of barium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., Wako Grade 1) is defined as 100%, and the total reflectance of each foamed molded product is expressed as a relative value. Show.

(Synthesis Example 1)
A heat medium circulating esterification reactor with a stirrer made of Hastelloy was charged with 100 mol% of high-purity terephthalic acid and 100 mol% of ethylene glycol, and 0.3 mol% of triethylamine was added to the total acid component, and 0.25 MPa. The esterification reaction was carried out for 2 hours while distilling water out of the system at 245 ° C. under pressure, and a mixture of bis (2-hydroxyethyl) terephthalate and oligomer having an esterification rate of 95% (hereinafter referred to as BHET mixture). Got. The BHET mixture was transported to a Hastelloy-made polycondensator with a stirrer, and antimony trioxide as a polycondensation catalyst was added to a residual amount of Sb of 270 ppm. Subsequently, it stirred at 245 degreeC for 10 minutes by the normal pressure in nitrogen atmosphere. Thereafter, while maintaining the temperature at 245 ° C., the pressure in the reaction system is gradually decreased to 13.3 Pa, and the first stage initial polycondensation is carried out for 50 minutes. Further, at 275 ° C. and 13.3 Pa, the IV is about 0.65 deciliter / The polycondensation reaction was carried out until grams. Subsequent to releasing the pressure, the prepolymer under slight pressure was discharged into cooling water in the form of a strand and rapidly cooled, and formed into a chip with a strand cutter to obtain a cylindrical chip. At the time of chip formation, the resin temperature from the polycondenser outlet to the nozzle pores was about 270 ° C., and the entire amount was chipped within about 30 minutes.

  The cooling water is obtained by treating industrial water (derived from river underground water) with a filter filtration device and an ion exchange device. The cooling water contains about 500 particles / 10 ml of particles having a particle size of 1 to 25 μm and has a sodium content of 0. 0.02 ppm (mass basis, the same shall apply hereinafter), magnesium content is 0.01 ppm, calcium content is 0.01 ppm, and silicon content is 0.11 ppm.

  Next, the obtained chip is immediately heat-treated at about 50 to about 150 ° C. in a vacuum dryer, treated by a vibration sieving step and an airflow classification step to remove fine powder and film-like material, and contain fine powder A crystallized prepolymer having an amount of about 50 ppm or less was obtained. The intrinsic viscosity was 0.63 deciliter / gram.

  Next, the crystallization prepolymer is sent to a crystallization apparatus, followed by crystallization at about 155 ° C. in a nitrogen atmosphere, and further preheated to about 200 ° C. in a nitrogen atmosphere, and then sent to a continuous solid-state polymerization reactor and about Solid state polymerization was performed at 205 ° C. After the solid phase polymerization, a fine powder was removed by continuous treatment in a sieving step and a fine powder removal step, to obtain a resin 1 having a fine powder content of about 50 ppm. The intrinsic viscosity of the obtained resin 1 was 1.0 deciliter / gram.

(Synthesis Example 2)
In Synthesis Example 1, 97 mol% terephthalic acid, 3 mol% isophthalic acid, and 100 mol% ethylene glycol were charged into the esterification reaction kettle, and the esterification reaction was performed. Resin 2 was obtained in the same manner as in Synthesis Example 1 except that germanium was used so that the residual Ge amount was 40 ppm. The intrinsic viscosity of the obtained resin was 0.85 deciliter / gram.

(Synthesis Example 3)
In Synthesis Example 1, an esterification reaction kettle is charged with 100 mol% terephthalic acid, 70 mol% ethylene glycol, and 30 mol% poly (tetramethylene oxide) glycol having a number average molecular weight of about 1000 to conduct an esterification reaction. In the same manner as in Synthesis Example 1 except that tetrabutyl titanate was used as the polycondensation catalyst, a resin 3 was obtained. The intrinsic viscosity of the obtained resin was 2.45 deciliter / gram.

(Synthesis Example 4)
In Synthesis Example 1, 70 mol% terephthalic acid, 30 mol% adipic acid, 100 mol% 1,4 butanediol were charged into the esterification reaction kettle, the esterification reaction was performed, and as a polycondensation catalyst Resin 4 was obtained in the same manner as in Synthesis Example 1 except that tetrabutyl titanate was used. The intrinsic viscosity of the obtained resin was 0.80 deciliter / gram.

(Synthesis Example 5)
In Synthesis Example 1, 100 mol% terephthalic acid and 100 mol% 1,4 butanediol were charged into an esterification reaction kettle to carry out an esterification reaction, and tetrabutyl titanate was used as a polycondensation catalyst. Resin 5 was obtained in the same manner as in Synthesis Example 1 except that The intrinsic viscosity of the obtained resin was 1.00 deciliter / gram.

(Synthesis Example 6)
In Synthesis Example 1, 100 mol% of naphthalenedicarboxylic acid and 100 mol% of 1,4 butanediol were charged into an esterification reaction kettle and subjected to esterification reaction, and tetrabutyl titanate was used as a polycondensation catalyst. Resin 6 was obtained in the same manner as in Synthesis Example 1 except that it was used. The intrinsic viscosity of the obtained resin was 0.75 deciliter / gram.

Example 1
As the polyester resin, 99.8 parts by mass of the resin 1 for the foam molded body, which was separately preliminarily dried, and 0.1 part by mass of the resin 3 for the foam molded body 4 and 0.1 part by mass of the resin 4 were supplied to the hopper directly above the extruder. The resulting mixture was melt-extruded using a twin-screw extruder adjusted to 280 ° C., rapidly cooled with a 40 ° C. cooling roll, and wound up to obtain a resin sheet 1 having a thickness of about 0.6 mm. A part of the resin sheet 1 was cut for measuring the degree of crystallinity, and then the rest was foamed by the following method to obtain a foam molded article 1.

That is, a roll was formed by wrapping the resin sheet 1 and a separator (olefin-based non-woven fabric (FT300 grade, manufactured by Nippon Vilene Co., Ltd.)), and the roll was filled with CO ₂ at 25 ° C. under 6.4 MPa. Holding in the chamber, the resin sheet 1 is impregnated with CO ₂ gas until the crystallinity of the resin sheet 1 reaches 25%. The roll was taken out from the pressure vessel, and while removing the separator, only the resin sheet 1 infiltrated with CO ₂ gas was continuously supplied to the hot-air circulating foaming furnace set at 240 ° C. so that the foaming time was 1 minute, and foamed. . The obtained foamed molded body 1 had a thickness of 1000 μm and an average cell diameter of 1 μm.

(Example 2)
In Example 1, resin sheet 2 was obtained in the same manner as in Example 1 except that 98 parts by mass of resin 1 for foamed molded body and 1 part by mass of resin 3 for foamed molded body and 1 part by mass of resin 4 were used as the polyester resin. And the foaming molding 2 was obtained.

Example 3
In Example 1, resin sheet 3 was obtained in the same manner as in Example 1 except that 90 parts by mass of resin 1 for foam molded body and 5 parts by mass of resin 3 for foam molded body and 5 parts by mass of resin 4 were used as the polyester resin. And the foaming molding 3 was obtained.

Example 4
In Example 1, as a polyester resin, 98 parts by mass of resin 1 for foam molding, modified styrene-ethylene / butylene-styrene copolymer (SEBS (f-SEBS), manufactured by JSR) and resin 4 for foam molding The resin sheet 4 and the foaming molding 4 were obtained like Example 1 except having used 1 mass part of each.

(Example 5)
In Example 1, as a polyester resin, 90 parts by mass of a resin 1 for foam molding, modified styrene-ethylene / butylene-styrene copolymer (SEBS (f-SEBS), manufactured by JSR) and resin 4 for foam molding The resin sheet 5 and the foaming molding 5 were obtained like Example 1 except having used 5 mass parts of each.

(Example 6)
In Example 1, resin sheet 6 was obtained in the same manner as in Example 1 except that 98 parts by mass of resin 1 for foam molded body and 1 part by mass of resin 3 for foam molded body and 1 part by mass of resin 5 were used as the polyester resin. And the foaming molding 6 was obtained.

(Example 7)
In Example 1, as polyester resin, resin sheet 7 was obtained in the same manner as Example 1 except that 90 parts by mass of foam molded body resin 1 and 5 parts by mass of foam molded body resin 3 and resin 5 were used. And the foaming molding 7 was obtained.

(Example 8)
In Example 1, resin sheet 2 was obtained in the same manner as in Example 1 except that 98 parts by mass of resin 2 for foamed molded product and 1 part by mass of resin 3 for foamed molded product and 1 part by mass of resin 4 were used as the polyester resin. And the foaming molding 2 was obtained.

Example 9
In Example 1, as polyester resin, resin sheet 2 was obtained in the same manner as Example 1 except that 90 parts by mass of resin 2 for foamed molded body and 5 parts by mass of resin 3 for foamed molded body and 4 parts of resin 4 were used. And the foaming molding 2 was obtained.

(Comparative Example 1)
In Example 1, the resin sheet 10 and the foaming molding 10 were obtained like Example 1 except having made the resin 1 for foaming moldings into 100 mass parts as polyester resin.

(Comparative Example 2)
In Example 1, as the polyester resin, the resin sheet 11 and the foamed molded body were used in the same manner as in Example 1 except that 98 parts by weight of the resin 1 for foamed molded body and 2 parts by weight of the resin 3 for foamed molded body were used. 11 was obtained.

(Comparative Example 3)
In Example 1, 98 parts by mass of resin 1 for foamed molded article and 2 parts by mass of modified styrene-ethylene / butylene-styrene copolymer (SEBS (f-SEBS), manufactured by JSR) were used as the polyester resin. Obtained the resin sheet 12 and the foaming molding 12 similarly to Example 1. FIG.

(Comparative Example 4)
In Example 1, resin sheet 13 was obtained in the same manner as in Example 1 except that 98 parts by mass of resin 1 for foam molded body and 1 part by mass of resin 3 for foam molded body and 1 part by mass of resin 6 were used as the polyester resin. And the foaming molding 13 was obtained.

(Comparative Example 5)
In Example 1, resin sheet 14 was obtained in the same manner as in Example 1 except that 90 parts by mass of resin 1 for foam molded body and 5 parts by mass of resin 3 for foam molded body and 5 parts by mass of resin 6 were used as the polyester resin. And the foaming molding 14 was obtained.

(Comparative Example 6)
In Example 1, resin sheet 15 was obtained in the same manner as in Example 1 except that 98 parts by mass of resin 1 for foamed molded body and 1 part by mass of resin 5 for foamed molded body and 1 part of resin 6 were used as the polyester resin. And the foaming molding 15 was obtained.

(Comparative Example 7)
In Example 1, resin sheet 16 was obtained in the same manner as in Example 1 except that 90 parts by mass of resin 1 for foam molded body and 5 parts by mass of resin 5 for foam molded body and 5 parts by mass of resin 6 were used as the polyester resin. And the foaming molding 16 was obtained.

  The crystallization degree of the obtained resin sheets 1 to 16 was measured by the above method, and the crystallization time was obtained. The average foam diameter and total reflectance of the foamed molded product were measured by the above method.

  The results are shown in Table 1.

  In Table 1, TPA is terephthalic acid, IPA is isophthalic acid, AA is adipic acid, NPA is naphthalene dicarboxylic acid, EG is ethylene glycol, DEG is diethylene glycol, PTMG is polytetramethylene oxide glycol, BD is 1,4-butanediol , F-SEBS means a modified styrene-ethylene / butylene-styrene copolymer.

  From Table 1, it was found that the crystallization speed of the resin sheet is increased by using a polymer having a polar group and two or more polyester resins having melting points or glass transition temperatures of 10 ° C. or more.

  In addition, it was found that the foamed molded product obtained from them had a total reflectance of a foamed molded product excellent in total reflectance.

  The resin composition for a foam molded article of the present invention can produce a resin sheet excellent in crystallinity in a short time. Moreover, since it is excellent in total reflectivity, it is suitable for use as reflectors for electric signboards, lighting fixtures, liquid crystal displays and the like.

Claims (7)

A resin composition for impregnating with a non-reactive gas and then heating to form a foamed molded article, which is derived from a polyester resin consisting of components derived from terephthalic acid and ethylene glycol, or derived from terephthalic acid, isophthalic acid and ethylene glycol the polyester resin comprising component mainly comprises a polymer having a polar group, the difference between the principal difference between the melting point than the polyester resin is 10 ° C. or higher or a glass transition temperature of the 10 ° C. or more lower polyester resin other polar group A resin composition for foamed molded articles, wherein the polymer having a polyester resin is a polyester resin obtained using a polyhydric alcohol selected from polypropylene oxide glycol, polytetramethylene oxide glycol, and mixtures thereof.   The resin composition for foam molded articles according to claim 1, wherein the main polyester resin is 60% by mass or more.   The resin composition for foam molded articles according to claim 1, wherein the polymer having a polar group is 0.1% by mass or more.   2. The resin composition for foam molded articles according to claim 1, wherein the polyester resin has a melting point difference of 10 ° C. or more or a glass transition temperature difference of 10 ° C. or more lower than that of the main polyester resin. . The resin composition for foam molded articles according to claim 1, wherein the time required for the crystallinity to exceed 25% when the crystallinity after impregnation with the non-reactive gas is evaluated is less than 42 hours. (However, the degree of crystallinity is obtained by cutting a sample piece of 35 mm length × 45 mm width × 0.6 mm thickness from a resin sheet and supercritical fluid processing test equipment (model: HV1-SC, Nisaka Manufacturing Co., Ltd.) And exposed to CO 2 gas at 25 ° C. and 5 MPa for a predetermined time, the sample piece was taken out of the supercritical fluid processing test apparatus and air-dried at 23 ° C. × 50% RH × 48 hours. The sample piece after air drying is set on a differential scanning calorimeter (EXSTAR6000, manufactured by SII Nano Technology Co., Ltd.), and the amount of heat based on crystallization and melting of the sample piece is measured while raising the temperature at 10 ° C./min. , Based on the following formula.
Crystallinity (%) = (A−B) / C
A: Calorie based on melting (J / g)
B: Heat quantity based on crystallization (J / g)
C: Heat of fusion of 100% crystallized PET (117.6 (J / g))   A resin sheet for foam-molded bodies obtained from the resin composition for foam-molded bodies according to claim 1. A foam molded article obtained from the resin sheet for foam molded article according to claim 6 .