JP2009203371A - Resin pellet and binder comprising it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pellet and a binder having good cohesiveness, block resistance, and moist heat-resistance, as well as moderate surface smoothness and flowability and excellent laminate workability. <P>SOLUTION: The resin pellet comprises a resin having a melting point of 70 to 170°C, a glass transition temperature of 30°C or less, and a melting viscosity at 200°C of 150 to 1,000 Pa s. The resin pellet has mass of 0.005 to 5 g per resin pellet particle and curved surface with curvature factor of 20 cm or less on the particle surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin excellent in adhesion to polyethylene terephthalate and metal, blocking resistance, heat and humidity resistance, and surface smoothness, and a binder comprising the same, and is useful as a coating material or protective material for flat cables and the like. It is related with an adhesive binder.

  Polyester resins typified by polyethylene terephthalate and polybutylene terephthalate are widely used in various fields as fibers, films, molding materials, etc., taking advantage of their excellent mechanical strength, thermal stability, hydrophobicity, and chemical resistance. .

  Moreover, it is possible to obtain copolymer polyester resins having various characteristics by changing the types of dicarboxylic acids and glycols that are constituents thereof, and they are widely used in adhesives, coating agents, ink binders, paints, etc. ing. Such a copolyester resin generally has excellent adhesion to plastics such as polyester, polycarbonate and polyvinyl chloride resin, or metal foil such as aluminum and copper.

  Utilizing these characteristics, copolymer polyester resins are also suitably used in adhesive applications such as flat cables having a structure in which a linear metal conductor is covered between two polyester films. Such flat cables have come to be widely used in recent years as wiring for AV equipment and computer equipment, which has been increased in density, or as wiring material for automobiles, and the demand for such flat cables is growing rapidly.

  In recent years, heat-meltable binders have been used in a wide range of fields because they do not use solvents and can eliminate pollution and save labor. About the thermoplastic resin used in this heat-meltable binder, after being melted by heating and closely adhering to the adherend, it has excellent adhesiveness that hardly causes delamination over a wide use temperature range, In addition to having a surface smoothness that results in a uniform and smooth surface, it should not stick out from the end face of the binder or transfer due to thermocompression roller contamination due to the transfer in the laminating process, while storing resin pellets and laminate sheets, It is required that blocking does not occur and that deterioration due to hydrolysis or the like hardly occur during heating and melting or during storage.

  Conventionally, a technique for imparting blocking resistance and moist heat resistance (hydrolysis resistance) while maintaining adhesion has been proposed (see, for example, Patent Document 1). However, if the melt viscosity in the heat-melted state becomes low, the binder may protrude from the end face in the laminating process, and the thermocompression roller may be soiled, and the smoothness of the laminate sheet surface may be reduced due to fish eyes or spots. There was a case.

In addition, a resin in which polyethylene, epoxy resin, organic alkoxysilane, or the like is added to a copolyester resin to achieve both adhesion and blocking resistance has been proposed (see, for example, Patent Documents 2 and 3). However, depending on the composition of this resin, the heat and humidity resistance is insufficient, the drying process at the time of resin mixing is complicated, and the melt viscosity is low due to the influence of organic alkoxysilane, and the binder protrudes from the end face in the lamination process. In some cases, the thermocompression roller may become dirty.
JP 2003-105302 A Japanese Patent No. 2590523 International Publication No. 1999029797 Pamphlet

  The present invention solves the above-mentioned various problems, and provides resin pellets and binders that have good adhesion, blocking resistance, moist heat resistance, surface smoothness, flowability, and excellent laminate operability. It is something to try.

  As a result of various studies to solve the above problems, the present inventor has reached the present invention. That is, the gist of the present invention is as follows.

  (1) Resin pellets made of a resin having a melting temperature of 70 to 170 ° C., a glass transition temperature of 30 ° C. or less, and a melt viscosity at 200 ° C. of 150 to 1000 Pa · s, and the mass per resin pellet is 0.005 A resin pellet having a curved surface with a radius of curvature of 20 cm or less on the particle surface of ˜5 g.

  (2) Copolymer comprising 30 to 70 mol% 1,4-benzenedicarboxylic acid as acid component, 30 to 70 mol% aliphatic carboxylic acid, and 20 mol% or more 1,4-dihydroxybutane as alcohol component The resin pellet according to (1), comprising a polyester resin.

  (3) Polyethylene or a copolymer-modified product thereof, polypropylene or a copolymer-modified product thereof, an epoxy resin, and at least from a group of copolymerized polyester resins having a glass transition temperature measured by a second scan of a differential scanning calorimeter of 40 ° C. or higher. One (1) or (2) resin pellet characterized by containing one.

  (4) Resin pellets according to (1) to (3), comprising particles of a compound containing silicon and / or magnesium element.

  (5) The resin pellet according to (4), wherein the compound containing silicon and / or magnesium element is talc having an average particle diameter of 5 μm or less.

  (6) A binder comprising the resin pellets of (1) to (5).

  According to the present invention, a resin pellet having excellent adhesion and surface smoothness to a metal plate, polyethylene terephthalate (PET) film or PET sheet, or cloth, and having good processability in the laminating step, and It is a binder and can be widely used as a hot melt adhesive.

  Hereinafter, the present invention will be described in detail.

  The resin pellet of the copolyester resin in the present invention needs to detect an endothermic peak at the second scan temperature rise when measured with a differential scanning calorimeter (DSC) at a temperature rise rate of 10 ° C./min. . When the endothermic peak is not detected, it is not preferable because the resin pellets and the sheets laminated with the binder are blocked. Moreover, since it becomes easy to transfer resin to a roller in a lamination process, it is not preferable.

  Further, the endothermic peak top (melting temperature) in the second scan in the above measurement needs to be 70 to 170 ° C., preferably 80 to 160 ° C., more preferably 80 to 150 ° C., and most preferably 90 to 140 ° C. When the melting temperature is less than 70 ° C., the heat resistance is reduced. For example, an insulating tape coated with the resin of the present invention containing a suitable flame retardant or filler in a PET film or the like for a flat cable, etc. This is not preferable because delamination (Z peeling) occurs in the processing step of applying heat to the substrate. When the melting temperature exceeds 170 ° C., the adhesion strength decreases, which is not preferable.

  Further, the heat of fusion of the endothermic peak in the second scan is preferably 0.5 J / g or more, more preferably 2 J / g or more, further preferably 5 J / g or more, and most preferably 15 J / g or more.

  Furthermore, the glass transition temperature (onset value) in the second scan in the above measurement needs to be 30 ° C. or lower, preferably 20 ° C. or lower, more preferably 10 ° C. or lower, more preferably 0 ° C. or lower, most preferably − 10 ° C or less. If the glass transition temperature exceeds 30 ° C., the adhesion strength decreases, which is not preferable.

  The melt viscosity at 200 ° C. of the resin pellet of the present invention is required to be 150 to 1000 Pa · s, preferably 200 to 800 Pa · s, more preferably 250 to 600 Pa · s, and most preferably 300 to 400 Pa · s.・ S. When the melt viscosity is less than 150 Pa · s, the binder flows in the laminating step and adheres to the laminating roller, which is not preferable. A melt viscosity exceeding 1000 Pa · s is not preferable because the binder does not sufficiently flow to the adherend and does not adhere.

  In the resin pellet, the mass per resin pellet needs to be 0.005 to 5 g, preferably 0.01 to 3 g, more preferably 0.02 to 1 g, and most preferably 0.03 to 0.5 g. When the mass per resin pellet is less than 0.005g, the frictional resistance between the resin pellets increases, and the resin pellets are clogged when introduced into an extrusion molding device, and the filler and flame retardant are not mixed uniformly. This is not preferable because fish eyes are easily generated. In addition, if the mass per resin pellet exceeds 5 g, unevenness and fish eyes are generated on the surface after lamination, the smoothness of the sheet surface is reduced, the sheets are blocked or transferred to a roller. Therefore, it is not preferable. Here, the mass per resin pellet is the mass of a typical resin pellet, and miscuts and crushed powder (dust) generated in part in the granulation process are not taken into consideration.

  Even if these miscuts and dust are contained in the resin pellets, they are preferably 10% by mass or less, more preferably 5% by mass, and most preferably 1% by mass. If it exceeds 10% by mass, fish eyes are generated in the laminate sheet, which is not preferable.

  The shape of the resin pellet is not particularly limited to a shape such as a substantially columnar shape, a spherical shape, a disk shape, a substantially cube shape, or a substantially prismatic shape, but it is easy to manufacture uniformly, and the resin pellet can be input to a processing machine. It is necessary to have a shape that is easy and does not affect the bite. As a preferable shape of the resin pellet, it is a substantially cylindrical shape, a spherical shape, or a substantially prismatic shape obtained from the melt-kneading, extruding, and cutting steps, and it is important that the shape of each grain is uniform. is there. The size of the resin pellets is 1 to 10 mm in diameter, preferably 3 to 8 mm, and the length is 1 to 10 mm, preferably 3 to 8 mm. Since aptitude differs, it is not limited by these.

  Furthermore, as a shape of the resin pellet, it is necessary to have a curved surface on a part of the surface or the entire surface. The radius of curvature needs to be 20 cm or less, preferably 10 cm or less, more preferably 5 cm or less, and most preferably 1 cm or less. The shape of the curved surface may be convex or concave with respect to the outside. If the entire surface of the resin pellets is flat or the radius of curvature exceeds 20cm, the resin may not be evenly dispersed due to friction and catching between the resin pellets in the extrusion process of the lamination process. In some cases, the surface smoothness may be lowered, and if the melt viscosity is lowered to overcome the drawbacks, the resin will flow too much and the rollers will be soiled and the operability will be lowered, which is not preferable. Moreover, when it does not have a curved surface in part or the whole surface, the contact area of resin pellets increases and it becomes easy to block. In order to handle the resin pellets, it is necessary to have a curved surface on a part or the entire surface of the resin pellets.

  The resin of the present invention includes, in addition to the copolyester resin, polyethylene or a copolymer modified product thereof, polypropylene or a copolymer modified product thereof, an epoxy resin, a glass transition temperature of 40 ° C. or higher, and a second scan of differential scanning calorimetry measurement. At least one of the other copolyester resins in which the melting temperature is not detected (hereinafter referred to as copolyester resin (B)) can be blended.

  The components other than the copolyester resin are preferably dispersed almost uniformly in the copolyester resin. However, the copolyester resin is present in a state of being coated on the surface of the resin pellet of the copolyester resin, or between the resin pellets. Even blends of these can be used.

  Polyethylene or a copolymer-modified product thereof, and polypropylene or a copolymer-modified product thereof can be added for the purpose of preventing blocking by improving crystallinity. Moreover, an epoxy resin and copolymer polyester resin (B) can be added in order to improve adhesiveness, maintaining blocking resistance.

  The content of polyethylene or a copolymer-modified product thereof, polypropylene or a copolymer-modified product thereof, an epoxy resin or a copolymerized polyester resin (B) with respect to the copolymerized polyester resin is 100 parts by mass or less with respect to 100 parts by mass of the copolymerized polyester resin. Is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, and most preferably 30 parts by mass or less. When the content exceeds 100 parts by mass, the adhesiveness is lowered, or delamination is caused by insufficient flexibility, and therefore, some problems occur for applications that require flexibility in addition to adhesiveness. Absent.

  For polyethylene or a copolymer-modified product thereof, high-density polyethylene, gas phase method linear low-density polyethylene, high-pressure method low-density polyethylene, polyethylene wax, or the like is used.

  As copolymerized modified products of polyethylene, propylene, styrene, 1-butene, 1-hexene, 1-octene, maleic anhydride, vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester and the like were copolymerized. Although it is possible to use those, the ratio of the monomer copolymerized with ethylene is preferably less than 10% by mass as a range that does not adversely affect the performance of the resin of the present invention.

  Regarding the melt viscosity of polyethylene (polypropylene) or its copolymer modified product, 0.01-50 g / 10 min is preferably used in MFR (JIS K6922-2) other than polyethylene wax (polypropylene wax), but 0.1-40 g / 10 min is more preferred. Preferably, 1 to 30 g / 10 min is more preferable, and 2 to 20 g / 10 min is most preferable. If the MFR is less than 0.01 g / 10 min or exceeds 50 g / 10 min, it is difficult to control the melt viscosity of the resin pellets of the present invention, or the dispersion with the copolyester is not successful and the blocking resistance is lowered. For polyethylene wax (polypropylene wax), the melt viscosity may be appropriately selected according to the amount used. As the shape, powder, granule, pellet, grease, or bead is used, but a powder is more preferably used.

  As the epoxy resin, bisphenol A type, bisphenol F type, cresol novolac type and the like are used. In order to improve the blocking resistance of the resin pellet of the present invention, the softening point is preferably 40 ° C or higher, more preferably 60 ° C or higher, further preferably 80 ° C or higher, and most preferably 100 ° C or higher.

  The glass transition temperature (onset) in the second scan in the differential scanning calorimeter of the copolymerized polyester resin (B) needs to be 40 ° C. or higher, preferably 50 ° C. or higher, more preferably 60 ° C. or higher, most preferably 65 ℃ or higher. A glass transition temperature (onset) of less than 40 ° C. is not preferable because the laminate sheets block each other.

  What is necessary is just to select suitably the monomer which comprises copolyester resin (B) so that a glass transition temperature may be 40 degreeC or more. In the case of a crystalline resin having a melting peak in DSC second scan, the melting peak top is preferably 170 ° C. or lower, more preferably 160 ° C. or lower, further preferably 150 ° C. or lower, and most preferably 140 ° C. or lower. In the case of an amorphous resin that does not have a melting peak in DSC second scan, it is preferably softened and melted in the range of 70 ° C to 150 ° C.

  The resin pellet of the present invention may contain particles of a compound containing silicon and / or magnesium element. The content is preferably 0.01 to 30% by mass in the resin pellet, more preferably 0.1 to 20% by mass, further preferably 0.5 to 10% by mass, and most preferably 1 to 5% by mass. If it is 0.01% by mass or less, the blocking resistance is undesirably lowered, and if it exceeds 30% by mass, the adhesion is lowered, which is not preferred.

  Of the compounds containing silicon and / or magnesium elements, silica and talc are preferably used. Further, the average particle size is preferably 5 μm or less, more preferably 3 μm or less.

  Next, the copolyester resin of the present invention will be described.

  First, the copolymerization ratio (unit: mol%) will be described. Polyester refers to a resin in which a carboxylic acid and a hydroxyl group are connected by an ester bond. The monocarboxylic acid or polyvalent carboxylic acid that constitutes the total of a plurality of monocarboxylic acid or polyvalent carboxylic acid components as 100 moles. The number of moles of acid is the copolymerization ratio (unit: mole%) with respect to 100 mole% of the acid component. For the alcohol component, the copolymerization ratio (unit: mol%) of the number of moles of the monoalcohol or polyhydric alcohol that constitutes the total of a plurality of monoalcohols or polyhydric alcohol components is 100 mol% And Moreover, about aliphatic carboxylic acids, such as hydroxycarboxylic acid, it shall consider as a component applicable to both an acid component and an alcohol component. For example, when the hydroxycarboxylic acid is contained in x mol%, the total of other acid components is (100-x) mol%, and the total of other alcohol components is also (100-x) mol%. .

  It is necessary that 1,4-benzenedicarboxylic acid is copolymerized as an acid component in an amount of 30 to 70 mol%, preferably 35 to 65 mol%, more preferably 40 to 60 mol%. If it is less than 30 mol%, the melting temperature is too low and the heat resistance is lowered, which is not preferable. If it exceeds 70 mol%, the melting temperature will be too high, the resin will be difficult to melt, and the adhesion will be reduced.

  The copolymerization ratio of the aliphatic carboxylic acid needs to be in the range of 30 to 70 mol%, preferably 35 to 65 mol%, more preferably 40 to 60 mol%. When the aliphatic carboxylic acid is less than 30 mol%, the melting temperature and the glass transition temperature are increased, and the adhesiveness is lowered, which is not preferable. On the other hand, if it exceeds 70 mol%, the melting temperature becomes too low and the heat resistance is lowered, which is not preferable.

  Aliphatic carboxylic acids include oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, octadecanedioic acid, eicosanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid, dimer acid, hydrogenated dimer acid and the like.

  Examples of hydroxycarboxylic acids include tetrahydrophthalic acid, lactic acid, oxirane, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy Hydroxycarboxylic acids such as valeric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid, and , Β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, and other aliphatic lactones.

  Among the aliphatic carboxylic acids and hydroxycarboxylic acids, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, and ε-caprolactone are preferably used.

  It is necessary that 1,4-dihydroxybutane is 20 mol% or more as an alcohol component, preferably 30 mol% or more, more preferably 40 mol% or more, and most preferably 50 mol% or more. If the copolymerization ratio of 1,4-dihydroxybutane is less than 20 mol%, the polycondensation rate of the polyester is remarkably reduced, which is not preferable.

  Other carboxylic acid components constituting the acid component include 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, 5-sodium sulfo-1,3 -Benzenedicarboxylic acid, 5-hydroxy-1,3-benzenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,3,4-benzenetricarboxylic acid, 1,2,4,5- Examples thereof include benzenetetracarboxylic acid, pyromellitic acid, and trimellitic acid. These may use anhydride as a monomer raw material.

  Examples of alcohol components other than 1,4-dihydroxybutane include 1,2-dihydroxyethane, 1,2-dihydroxypropane, 1,3-dihydroxypropane, 1,2-dihydroxybutane, 1,3-dihydroxybutane, 2- Methyl-1,3-dihydroxypropane, 2,2-diethyl-1,3-dihydroxypropane, 2-ethyl-2-methyl-1,3-dihydroxypropane, 2-butyl-2-ethyl-1,3-dihydroxy Propane, 2,2'-dimethyl-1,3-dihydroxypropane, 3-methyl-1,5-dihydroxypentane, 1,5-dihydroxypentane, 1,6-dihydroxyhexane, 1,7-dihydroxyheptane, 1, 8-dihydroxyoctane, 1,9-dihydroxynonane, 1,10-dihydroxydecane, 3-oxapentane-1,5-diol, 2,2 '-(1,2-ethanediylbis (oxy))-bisethanol, bis (2-hydroxypropyl) ether, 2- (2- (2-hydroxypropoxy) Ii) propoxy) -1-propanol, bisphenol A, bisphenol S, bisphenol C, bisphenol Z, bisphenol AP, ethylene oxide adduct or propylene oxide adduct of 4,4′-biphenol, 1,3-bis (β-hydroxy) Ethoxy) benzene, 1,2-bis (hydroxymethyl) cyclohexane, 1,3-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxymethyl) cyclohexane, poly (oxyethin-1,2-diyl), poly ( Oxybutane-1,4-diyl), poly (oxypropane-1,3-diyl), glycerol, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol, 2-methyl-2- (hydroxymethyl) ) -1,3-propanediol, tetrakis (hydroxymethyl) methane, α-methylglucose, mannitol, sorbitol and the like.

  These do not necessarily need to be used alone, and may be used in combination of two or more according to the properties desired to be imparted to the resin.

  Moreover, monocarboxylic acid and monoalcohol may be copolymerized with the copolyester resin. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. Examples of the alcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, 2-phenoxyethanol and the like.

  Furthermore, the resin pellets of the present invention include, as necessary, a heat stabilizer such as phosphoric acid, an antioxidant such as a hindered phenol compound, a hindered amine compound, and a thioether compound, a lubricant such as talc and silica, and titanium oxide. Conventionally known additives such as pigments, fillers, antistatic agents and foaming agents may be contained.

  The molecular weight of the copolyester resin is preferably 7000 to 100,000 in terms of number average molecular weight, more preferably 10,000 to 70,000, and most preferably 20,000 to 50,000. When the molecular weight is lower than 7000, the melt viscosity is decreased, and when the molecular weight is higher than 100,000, the melt viscosity is increased.

  Copolyester resin can be produced by combining the aforementioned monomers and polycondensing by a known method. For example, all monomer components and / or low polymers thereof are 180 to 250 ° C. under an inert atmosphere. An esterification reaction is carried out by reacting for about 2.5 to 10 hours, and then a polycondensation reaction is performed at a temperature of 220 to 280 ° C. under a reduced pressure of 130 Pa or less until a desired molecular weight is reached to obtain a copolyester resin. it can.

  In esterification and polycondensation reactions, titanium compounds such as tetrabutyl titanate, metal acetates such as zinc acetate, magnesium acetate, and zinc acetate, antimony trioxide, hydroxybutyltin oxide, tin octylate, etc. Polymerization is carried out using the organotin compound. In this case, the amount of catalyst used is preferably 0.1 to 20 × 10 −4 mol per 1 mol of the acid component.

  In addition, after the polycondensation reaction is completed, a predetermined amount of a polybasic acid component, a polyvalent glycol component, or the like is added, and depolymerization can be performed in an inert atmosphere.

  As a method of mixing polyethylene or a copolymer-modified product thereof, polypropylene or a copolymer-modified product thereof, an epoxy resin or a copolymerized polyester resin (B), the copolymer polyester resin obtained by the polycondensation reaction is sheared with a kneader. Or by kneading in a molten state, simply dry blending the resin pellets of copolymer polyester resin and polyolefin resin pellets or powders, or adding polyolefin to the esterification or polycondensation process of copolymer polyester resin The method of mixing etc. is mention | raise | lifted.

  Next, a method for molding a resin into a resin pellet having a desired shape will be described. As a method of forming resin pellets, generally, after discharging in the form of a sheet, crystallization or cooling while appropriately pulverizing or dicing, or extruding into a round or elliptical shape into a strand, an appropriate length There is a method of cutting to the right, or a method of extruding to an appropriate length in water and then cutting off in water.

  In the method in which the strands or resin pellets are cut by an appropriate length after being melt-kneaded and then extruded, the strands or the resin pellets are not blocked, that is, before and / or after the strands are cut. It is preferable to provide a step of crystallizing the resin pellets while cooling in water and / or air so that the resin pellets do not contact each other as much as possible. Here, let the discharge time before strand cutting be ta, and let the discharge time after strand cutting be tb. The discharge time after strand cutting is from immediately after strand cutting, immediately before entering the dehydrator when passing through the dehydrator, immediately before entering the classifier without passing through the dehydrator, or to either the dehydrator or the classifier. In the case of collecting directly in a container such as a bag or silo without passing through, it means the time of the cooling process until just before that.

  Usually, before the cut resin pellets are collected in a container, a dehydration step using a dehydrator and a classification step using a classifier can be added as necessary.

  In the method of pulverizing or cutting in a dice shape after paying out in the form of a sheet, it is not normally used preferably because the resin pellet has no curved surface.

  As a method for imparting a curved surface, a method of cutting the strand with an appropriate length after extruding the strand so that the cross-sectional shape becomes round or elliptical, or by extruding to an appropriate length in water and then cutting it off in water The method of rounding the resin with water pressure needs to be crystallized before the resin pellets come into close contact with each other so as not to block when packing the cut resin pellets.

  As an index of easiness of crystallization, the resin in a molten state, which has been heated above the melting temperature and becomes transparent due to the collapse of the crystal structure, is immersed in water and cooled, and then pulled up to the atmosphere at a predetermined temperature. The time until the resin pellet surface begins to whiten is measured as the crystallization time (tc) by leaving it in the atmosphere as it is, and measuring the time until the resin pellet surface begins to whiten.

  The crystallization time tc of the resin pellet is preferably 10 seconds to 20 minutes, more preferably 20 seconds to 10 minutes, and even more preferably 30 seconds to 5 minutes. If it is 10 seconds or less, the resin shrinks excessively during crystallization, and the adhesive force when bonded is reduced, which is not preferable. On the other hand, if it exceeds 20 minutes, the resin pellets may be blocked or the laminated sheets may be blocked.

  In the present application, it is important to perform crystallization at the same time as cooling the extruded strand in water and / or air in the polymerization discharge or the melt-kneading with the additive. It cuts, providing a curved surface.

  Moreover, the resin pellet can use the method of giving sufficient crystallization at a post process in addition to crystallization at the time of cooling. Here, the post-process refers to the process after the dehydration process when there is a dehydration process, and refers to the process after the process when there is no dehydration process. In the present application, crystallization at the time of cooling is sufficient for crystallization to the extent that blocking can be suppressed, and if the cooling zone cannot be made sufficiently long, it is easier to make the device more compact by crystallizing in a later step. More preferable in terms.

The crystallization time when granulating the resin pellet can be obtained as the cooling time of the strand. That is, it is determined by the strand cooling time ( ta + tb), where ta is the discharge time before strand cutting, and tb is the discharge time immediately before collecting the resin pellets after strand cutting. It is preferable that there is a relationship of 0.3 ≦ (ta + tb) /tc≦2.0 between the strand cooling time (ta + tb) and the resin pellet crystallization time tc. More preferably, 0.5 ≦ (ta + tb) /tc≦1.5, and even more preferably 0.7 ≦ (ta + tb) /tc≦1.1. If it is less than 0.3, the resin pellets are blocked, which is not preferable. Exceeding 2.0 is not preferable because productivity decreases.

  The copolyester resin of the present invention is used as a hot melt adhesive, as a binder in the electrical, electronic field, mechanical field, food field, building field, automobile field, textile field, electrical field, and electronic field, specifically as an electric wire. It can be suitably used as an electrical component such as a coating agent, a flat cable or a reinforcing plate thereof.

The present invention will be specifically described below with reference to examples.
(1) Composition of copolymer polyester resin 1H-NMR measurement was performed using an NMR measuring apparatus JNM-LA400 manufactured by JEOL Ltd., and the composition was determined from the peak intensity of each copolymer component. Deuterated trifluoroacetic acid was used as a measurement solvent for measuring the composition of the copolyester resin.
(2) Number average molecular weight of copolymerized polyester resin The number average molecular weight is determined by GPC analysis (liquid feeding unit LC-10ADvp type and UV-visible spectrophotometer SPD-6AV type manufactured by Shimadzu Corporation), detection wavelength: 254 nm, solvent : Tetrahydrofuran, polystyrene conversion).
(3) Melt viscosity of resin pellets Measured with a Brookfield melt viscometer DV-II + PRO type at a resin temperature of 200 ° C. and a shear rate of 1.25 / s. After starting the melting, it was rotated for about 25 minutes, and the value of the melt viscosity at the time when the viscosity was stabilized at almost the elapsed time was read.
(4) Curvature radius of resin pellet Five arbitrary resin pellets are sampled, and each pellet is photographed with a CCD camera from six directions up, down, front, back, left, and right, and the image is enlarged 5 to 20 times. First, a portion having the most curved surface is selected for the first surface, and the local curvature radius is calculated from the coordinates of the three pellet contours (three-point arc method). The same measurement was performed on the other five surfaces, the maximum value of the obtained six data was obtained, and the average value was taken as the radius of curvature.
(5) Mass of resin pellet The mass of 100 resin pellets was measured with an electronic balance, and the value obtained by dividing the mass by 100 was defined as mass (g) per resin pellet. Mass was measured to an accuracy of 0.1 mg.
(6) Melting temperature (Tm) and glass transition temperature (Tg) of resin pellets
Using 10 mg of resin pellets as a sample, using a DSC (Differential Scanning Calorimetry) apparatus (Diamond DSC manufactured by PerkinElmer Co., Ltd.), measurement is performed at a temperature rising rate of 10 ° C./min. The onset of two bending point temperatures derived from the glass transition in the obtained temperature rise curve was defined as the glass transition temperature. In all cases, the value at the temperature increase in the second scan after cooling from 200 ° C. to −50 ° C. was read at a temperature decrease rate of 50 ° C./min.
(7) Blocking resistance of resin pellets The pellets discharged after completion of polymerization or kneading of the resin were visually observed to examine whether the pellets were fused. If it was, it was rejected.
(8) Crystallization time of resin pellet (tc)
Place an appropriate amount of resin pellets on a stainless steel plate every 1 cm so that the resin pellets do not touch each other, put it in a 200 ° C oven and melt it, then immerse it in a 10 ° C water bath for 2 seconds, then pull it up while standing the plate. Stand the board under an atmosphere of 23 ℃. Starting from this point in time, the time until the resin surface is visually whitened is defined as tc.

  Using the obtained copolymer polyester resin pellets, the following hot melt adhesives were evaluated.

(Creation of evaluation coating film)
Here, the obtained resin pellet was melted and heated at 200 ° C., applied to a PET film having a thickness of 38 μm so as to have a thickness of 50 μm, and allowed to stand at room temperature for 17 hours and cooled.
(9) PET adhesion The coated surfaces of the coated films were put together and pressed and laminated at 180 ° C. with a load of 1 N for 1 minute. The obtained laminate sheet was cut into a 25 mm wide strip and subjected to a peel test at room temperature. A peel strength of 20 N / 25 mm or more was determined to be acceptable, and less than 20 N / 25 mm was determined to be unacceptable.
(10) Blocking resistance The PET film was coated on the coated surface of the coated film, applied with a load of 300 N, and allowed to stand at 40 ° C. for 12 hours. The treated sheet was cut into a 25 mm width strip and subjected to a 180 ° C. peel test at a peel speed of 50 mm / min. The adhesive strength was 2N / 25 mm or less.
(11) Heat resistance The coated surfaces of the coated films were put together and pressed at 180 ° C. with a load of 1 N for 1 minute for lamination. The obtained laminate sheet was cut into a strip of 25 mm width and subjected to a peel test in an atmosphere at 80 ° C., and a peel strength of 15 N / 25 mm or more was determined to be acceptable, and less than 15 N / 25 mm was determined to be unacceptable.
(12) Flowability The coated film was suspended in a hot air dryer with an internal temperature of 170 ° C. for 10 minutes so that the sheet was vertical, and after the heat treatment was completed, it was taken out and immediately immersed in ice water. It was taken out from the ice water, the appearance was observed, and if the coated surface did not flow, it was judged to be acceptable, and if it was, judged to be unacceptable.
(13) Surface smoothness
Using the coating film on which the anti-blocking property of (10) was evaluated, the coated surface was observed with a polarizing microscope (magnification 40 to 70 times), and it was confirmed whether fish eyes were present. Those in which fish eyes were not confirmed were judged as acceptable, and those in which one or more were confirmed were judged as unacceptable.

(Polymerization of copolymer polyester resin)
Production Example 1
As an acid component, 50 mol% of 1,4-benzenedicarboxylic acid, 35 mol% of sebacic acid, 15 mol% of 1,4-cyclohexanedicarboxylic acid, 95 mol% of 1,4-butylene glycol as an alcohol component, polytetra The raw material is charged into an esterification reaction can so that the content of methylene glycol 1000 is 5 mol%, esterified, transferred to a polycondensation can, and 1 mol of tetrabutyl titanate constituting the polyester resin. In contrast, 0.0004 mol is added and a polycondensation reaction is performed at 240 ° C., stirring is stopped at a predetermined viscosity, the resin is extruded into a sheet shape, and after this sheet crystallizes and becomes opaque, it is introduced into a cutter and formed into a dice shape. Cut to obtain resin pellets of copolymer polyester resin P-1. Table 1 shows the composition and number average molecular weight of the obtained copolyester resin P-1.

Production Example 2 to Production Example 10
According to Table 1, resin pellets of copolymer polyester resins P-2 to P-10 were obtained.

(Production of resin pellets)
The following resins were used for the copolymerized polyester resin.

a) LDPE: Low density polyethylene (LC720 manufactured by Nippon Polyethylene Co., Ltd.)
b) HDPE: high density polyethylene (HJ362N manufactured by Nippon Polyethylene Co., Ltd.)
c) PP: High density polypropylene (FG3DC manufactured by Nippon Polypro Co., Ltd.)
d) PE-WAX: Polyethylene wax (Honeywell Acumist C-5)
e) PES-1: Copolymerized polyester resin pellets (UE-9600 manufactured by Unitika Ltd.), Tg = 65 ° C.
f) Talc: Talc (Nihon Talc Co., Ltd. P-8)
g) Silica: (SY310P manufactured by Fuji Silysia)
h) Epoxy: Epoxy resin (JER Epicoat 1007)

Example 1
Biaxial polyester resin P-1 obtained in Production Example 1 was mixed uniformly with 100 parts by mass of LDPE as an additive resin so as to be 1 part by mass, and the cylinder temperature was heated to 120 to 150 ° C. The product was introduced into a kneader and discharged as a strand from a circular nozzle. The discharged strand is brought into contact with water at 10 ° C. for 5 seconds (ta), then cut into resin pellets, and the resin pellets are put into a water bath set at a water temperature of 12 ° C., and there is a water flow so that the resin pellets do not settle. After discharging the resin into the water bath for 10 seconds (tb), the resin pellet was received in a bag through a dehydrator. The obtained resin pellets had an average mass of 0.025 g per grain, the shape was substantially cylindrical, and the radius of curvature of the resin pellets was 0.15 cm. The melting temperature was 106 ° C and the glass transition temperature was less than -40 ° C. The melt viscosity at 200 ° C. was 250 Pa · s, Tc was 20 seconds, and (Ta + Tb) /Tc=0.75. Next, the laminated sheet obtained by applying the obtained resin pellets to a PET sheet was examined for blocking resistance, PET adhesion, heat resistance, flowability, and surface characteristics. The above evaluation results are shown in Table 2.

Example 2
Co-polyester resin P-1 was used as 100 parts by mass, and PE-WAX was used as 0.1 part by mass as an additive resin. The addition method was added together when the monomer raw material was charged into the esterification reactor. Resin which reached | attained predetermined | prescribed viscosity with the superposition | polymerization can was paid out with the submerged cutter so that it might become the resin shape in a table | surface by the conditions in a table | surface. The physical properties of the laminate sheet were all acceptable. The above evaluation results are shown in Table 2.

Example 3
A biaxial kneader in which resin pellets were mixed so that PES-1 as an additive resin was 25 parts by mass with respect to 100 parts by mass of copolymer polyester resin P-4, and then the cylinder temperature was heated to 120 to 150 ° C. And discharged as a strand from a circular nozzle. The discharged strand is brought into contact with water at 10 ° C. for 600 seconds, then cut into resin pellets, and the resin pellets are put into a water bath set at a water temperature of 12 ° C., and placed in a water bath with a water flow so that the resin pellets do not settle. After discharging the resin for 3 seconds, the resin pellets were received in a bag through a dehydrator. The obtained resin pellets had an average mass of 100 g per grain and 1.8 g, and the shape was substantially cylindrical with a curvature radius of 0.4 cm. The melting temperature was 149 ° C and the glass transition temperature was 17 ° C. The melt viscosity at 200 ° C. was 220 Pa · s, tc was 1080 seconds, and (ta + tb) /tc=0.56. The physical properties of the laminate sheet were all acceptable. The above evaluation results are shown in Table 2.

Example 4 and Example 5
According to the formulation in Table 2, the same method as in Example 1 was performed. The evaluation results are shown in Table 2.

Example 6
The copolymerized polyester resin having the composition shown in Table 1 was polymerized in a polymerization can to a predetermined viscosity, and then dispensed with an underwater cutter under the conditions shown in the table without adding an additional resin. The resin pellet was spherical.

Example 7 and Example 8
The same procedure as in Example 1 was followed in accordance with the formulation in Table 2 except that the additive was blended. The evaluation results are shown in Table 2.

Comparative Examples 1 to 6
According to the formulation in Table 3, the same procedure as in Example 1 was performed. The results are shown in Table 3.

  In Examples 1 to 8, various blending was performed on the obtained copolymer polyester resin, and resin pellets satisfying claim 1 were obtained, so that PET adhesion of a laminate sheet obtained by coating these copolymer polyester resins was achieved. , Blocking resistance, heat resistance, flowability, and surface smoothness were all excellent.

Comparative Example 1
Since the molecular weight was low in comparison with the composition, the melt viscosity was low and the flowability was unacceptable.

Comparative Example 2
Since the radius of curvature of the resin pellet was too large, an undissolved component was generated, and that portion became a nucleus and fish eyes were generated. From the melting point, the core of the fish eye portion was determined to be an undissolved component of the resin pellet component.

Comparative Example 3
Since the HDPE blending amount was 30% by weight, the melt viscosity of the resin pellets increased, the flowability of the resin decreased with the laminate, and the PET adhesion decreased.

Comparative Example 4
The copolyester of the composition containing no aliphatic carboxylic acid was used, and the additive was not added, so the melting point was high and the glass transition point was too high. .

Comparative Example 5
Since the copolymerization ratio of 1,4-benzenedicarboxylic acid was less than the predetermined ratio, the crystallinity was lowered and the blocking resistance was rejected. Moreover, melting temperature became low and heat resistance failed.

Comparative Example 6
Additives were not added to the copolymerized polyester resin, and the extruded sheet was made into resin pellets that were diced, so that the shape did not have a curved surface, and fish eyes were generated on the laminating sheet. When the melting temperature and metal analysis were performed, the fish eye part was mainly unmelted resin.

Comparative Example 7
The mass per resin pellet became too small, undissolved components were generated, and that portion became the nucleus and fish eyes were generated. From the melting point of the core of the fish eye part, it was determined that the resin pellet component was an undissolved component.

Claims (6)

  A resin pellet made of a resin having a melting temperature of 70 to 170 ° C., a glass transition temperature of 30 ° C. or lower, and a melt viscosity at 200 ° C. of 150 to 1000 Pa · s, and a mass per resin pellet of 0.005 to 5 g, A resin pellet characterized by having a curved surface with a curvature radius of 20 cm or less on the particle surface.   A copolymer polyester resin comprising 30 to 70 mol% 1,4-benzenedicarboxylic acid as an acid component and 30 to 70 mol% aliphatic carboxylic acid, and 20 mol% or more 1,4-dihydroxybutane as an alcohol component. The resin pellet according to claim 1, which is contained.   At least one selected from the group consisting of polyethylene or a copolymer-modified product thereof, polypropylene or a copolymer-modified product thereof, an epoxy resin, and a copolymerized polyester resin having a glass transition temperature of 40 ° C. or higher measured by a second scan of a differential scanning calorimeter The resin pellet according to claim 1, wherein the resin pellet is contained.   The resin pellet according to any one of claims 1 to 3, comprising particles of a compound containing silicon and / or magnesium element.   The resin pellet according to claim 4, wherein the compound containing silicon and / or magnesium element is talc having an average particle diameter of 5 μm or less. The binder which uses the resin pellet in any one of Claims 1-5.