JPS6223765B2 - - Google Patents

Description

[Detailed description of the invention]

[] BACKGROUND OF THE INVENTION The present invention relates to a method for producing modified resins. More specifically, the present invention relates to a method for modifying thermoplastic resins. For the purpose of imparting new functions to existing thermoplastic resins, grafting of various monomers is actively carried out. For example, it is effective to graft a monomer having a functional group or a polar group to impart adhesiveness, paintability, printability, crosslinkability, etc. to an olefin polymer. Various methods have been proposed for graft polymerization, but one method that takes advantage of the fact that the base material or backbone polymer is a thermoplastic resin is to use a radical generator such as an organic peroxide. There is a method in which a radically polymerizable monomer is plasticized and kneaded in an extruder to cause a graft reaction therebetween.
In this case, the thermoplastic resin used is either pellet-like particles or powder produced by a polymerization reaction. However, in this method, especially when the monomer and/or radical polymerization initiator are liquid, they are mixed with a powder to granular thermoplastic resin in a conventional mixer, and then plasticized in an extruder to carry out the graft reaction. In doing so, the following are often experienced: 1 When the entire amount of granules is used as the thermoplastic resin, the resulting graft reaction product contains a lot of fissures (that is, infusible materials with a high degree of crosslinking in parts), and the hue deteriorates due to partial deterioration.
MI runout and various other unexpected quality deteriorations that are thought to be caused by the non-uniformity of the grafting reaction occur. This problem may be solved to some extent by thorough mixing before plasticizing and kneading in the extruder, but no matter how thorough the premixing is, the Poor biting into the extrusion screw and poor kneading in the kneading section within the extruder occur, resulting in large extrusion fluctuations. As a result, the residence time of the reactants in the extruder, ie, the reaction time, varies, making it difficult to continuously produce products of uniform quality over a long period of time. 2 Even if the entire thermoplastic resin is used in powder form, the same quality problems as in 1 will occur, especially if the monomer and/or polymerization initiator are liquid and viscous, or if the amount added is large. The problem arises. Further, even if sufficient mixing with such a liquid component is carried out, the thermoplastic resin powder tends to aggregate and solidify, resulting in frequent bridging in the hopper and the like, resulting in large extrusion fluctuations. Even when a screw-type extruder is used to blend inorganic filler powder into thermoplastic resin powder, the resin-filler powder mixture is not easily absorbed into the extrusion screw, resulting in various problems with the extruded pellets. You can see some points. Regarding this point, an improved method has been proposed in which a small amount of thermoplastic resin particles or lumps is blended into this powder mixture and extrusion is carried out (Japanese Patent Laid-Open No. 48-96658, U.S. Pat. No. 3,919,164). (see book). [] Summary of the Invention The present invention aims to solve the above-mentioned problems by using a specific mixture of granules and powder as a thermoplastic resin to be graft-modified with a liquid polymerizable monomer. It aims to achieve this purpose. Therefore, the method for producing a modified resin according to the present invention is characterized by polymerizing component C by melt-kneading a mixture containing the following components A, B, and C under polymerization conditions for component C. . A Thermoplastic resin granules that passed through 4 meshes of JIS standard sieves but not 12 meshes, B Thermoplastic resin powders that passed 20 meshes of JIS standard sieves, C Polymerizable liquid monomer. However, the weight ratio of these three components is as follows. A/B=99/1 to 80/20 C/A+B=0.1/100 to 10/100 In this way, the present invention does not use each of the conventionally employed granular or powdered materials alone. It is unique in that it uses both in an appropriate ratio. According to the present invention, an ordinary extruder can be used without any special modification, and significant improvements can be achieved in terms of the weight, hue, MI runout, and other quality or performance of the grafted reactants. can. That is, this three-component mixture is well penetrated into the screw of the extruder, resulting in less fluctuation in extrusion and, therefore, good equipment operability and productivity. In addition, since the dispersibility of the resin particles or powder and the monomer is good, there are few fish eyes, and since the amount of unreacted monomer is small, improvements can be seen in the adhesiveness, heat resistance, hue, etc. of the resulting modified resin. [] Detailed Description of the Invention The raw material of the present invention is a mixture containing the three components described above. 1. Thermoplastic resin granules (A) All thermoplastic resins that can be modified by a graft reaction in a molten state are subject to the present invention. Typical examples of such thermoplastic resins include homopolymers of olefins such as ethylene, propylene, butene, and copolymers thereof with each other or with other copolymerizable monomers, such as polyethylene, isotactic polypropylene, ethylene, etc. - propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, chloroethylene polymers, e.g. polyvinyl chloride, vinylbenzene polymers e.g. polystyrene, styrene-methyl methacrylate copolymers , styrene-acrylonitrile copolymer, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and others. These can be used alone or in combination. According to the invention, these thermoplastic resins are
Pass through a 4-mesh sieve using a JIS standard sieve (pass)
The granules must not pass through the 12-mesh sieve. The individual particles of such granules are cylindrical,
It may be prismatic, spherical, tablet-like, or any other shape that has the above-mentioned sieving properties and can be called granular.
Granules produced in conventional granulators can generally be used. The amount used is as described below. 2. Thermoplastic resin powder (B) The same or different thermoplastic resins as the above-mentioned granular thermoplastic resin (A) can be used alone or in combination. In the present invention, the powder to be used in combination with the above-mentioned granules must pass 20 meshes on a JIS standard sieve. Such a powder can be produced by mechanical or chemical grinding (e.g., precipitation from a solution) of the granules, and can also be produced by recovering the product in powder form during the production of the thermoplastic resin. It can be obtained by etc. The shape of the individual particles of the powder is the same as that for the granules described above. The amount used is as described below. 3 Polymerizable liquid monomer (C) Polymerizable means capable of radical polymerization.
Liquid means substantially fluid under polymerization conditions, and is not limited to being liquid at room temperature or pressure. It also includes substances that are soluble in solvents, other monomers used in combination, polymerization initiators, and other coexisting components and can exist in the polymerization system as a solution, even if they are not liquid themselves under polymerization conditions. (details below). Such monomers are generally compounds containing at least one ethylenically unsaturated bond. Specifically, for example, ethylenically unsaturated carboxylic acids (especially monocarboxylic acids), esters and salts thereof, such as acrylic acid, methacrylic acid, acrylic or lower alkyl (about C ₁ to _{C 4} ) esters of methacrylic acid, acrylic or glycidyl ester of methacrylic acid, acrylonitrile, methacrylonitrile, vinylbenzene and its derivatives, such as styrene, vinyltoluene, α-methylstyrene, vinylpyridine, methylvinylpyridine, acrylamide, methacrylamide, maleic anhydride, divinylbenzene, diacrylic or ethylene glycol dimethacrylate, and others. A particularly preferable group of monomers for use in the present invention are radically polymerizable silane compounds represented by the following general formula. RR′SiY ₂ (here, R is an ethylenically unsaturated aliphatic hydrocarbon group or hydrocarbonoxy group, Y is an organic group having reactivity such as hydrolysis, and R′ is a saturated aliphatic (a hydrocarbon group, an ethylenically unsaturated aliphatic hydrocarbon group or a hydrocarbonoxy group which is the same as or different from R, or a reactive organic group which is the same or different from Y). Examples of the group R of this silane compound include vinyl, allyl, butenyl, cyclohexenyl, cyclopentadienyl, _CH2 =C( _CH3 )COO( _CH2 ) _3- , _CH2 =C
(CH ₃ )COO CH ₂ CH ₂ O(CH ₂ ) ₃ −, and CH ₂ =C(CH ₃ )COO CH ₂ O CH ₂ CH
(OH)CH ₂ O(CH ₂ ) ₃ − and the like can be mentioned. The group Y is a group having reactivity such as hydrolysis, and specifically includes (i) an alkoxy group such as a methoxy group, an ethoxy group, and a butoxy group, (ii) a formyloxy group, an acetoxy group, and a propion group. Acyloxy group such as oxy group, (iii) -ON=C( _CH3 ) _2- , -ON=C
( _CH3 ) _C2H5 , and oxime groups such _as -ON=C( _{C6H5 ) 2} , and (iv) _-NHCH3 , -
Mention may be made _of substituted amino groups such _{as NHC2H5} , and -NH( _C6H5 ), among others. R' is selected from the group of R and Y, or is an alkyl group of about _C1 to _C4 . A modified resin modified with such a silane compound can be crosslinked by contacting it with a silanol condensation catalyst and water. These monomers can be used alone or in combination. Among these monomers, those which are not themselves liquid under polymerization conditions can be used in the form of a solution dissolved in a suitable solvent. For example, in the case of maleic anhydride, it can be used by dissolving it in a monomer or polymerizable solvent such as styrene, a non-polymerizable solvent such as toluene, or a polymerization initiator such as 3,5,5-trimethylhexanoyl peroxide. . 4 Amount Ratio The weight ratio of these three essential components is as follows. 1 Thermoplastic resin granules (A)/same powder (B) =, 99/1
~80/20 2 Polymerizable liquid monomer (C)/thermoplastic resin granules (A)+
The same powder (B) = 0.1 to 10/100, preferably 0.1 to 5/
100 5 Polymerization initiator When melt-kneading the mixture of the three essential components A to C, a radical polymerization initiator is used in order to polymerize the polymerizable liquid monomer and cause grafting to the thermoplastic resin. It is preferable. Specific examples of polymerization initiators that can be used in the present invention include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide,
2,5-di(peroxybenzoate)hexyne-3,1,3-bis(t-butyl-peroxyisopropyl)benzene, lauroyl peroxide, t-butyl peracetate, 2,5-dimethyl-2,5- Di(t-butylperoxy)hexane-3, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylperbenzoate, 3,5,5-trimethylhexanoyl peroxide, There are azobis-isobutyronitrile, dimethylazodiisobutyrate, and others. The amount of the polymerization initiator used should be sufficient for the polymerization of the polymerizable liquid monomer, preferably for the graft reaction between thermoplastic resin particles and powder, and also for the crosslinking reaction and decomposition reaction of the thermoplastic resin. It should be selected within a range in which other deterioration reactions do not become the main reaction. Specifically, for example, the amount is usually about 0.005 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin particles and powder. 0.01 to 2 parts by weight is preferred. 6. Other Auxiliary Components Various auxiliary components such as antioxidants, ultraviolet absorbers, plasticizers, pigments, fillers, etc. may be added as necessary. When it is desired to use a solid monomer, its non-reactive solvent can be used. The solvent in that case is generally small. 7. Modification step The three essential components A to C and desired auxiliary components are physically mixed, and this mixture is melt-kneaded under polymerization conditions of the polymerizable liquid monomer to modify or graft modify the thermoplastic resin. Physical mixing prior to melt-kneading can be carried out by any conventional high-speed mixer, tumbler mixer, V-blender, or other equipment commonly used for mixing particulate solids or liquids. It is preferable to mix as thoroughly as possible during this process. In order to melt and knead the physically mixed mixture, it is necessary to melt and knead the thermoplastic resin at a temperature at which polymerization of the polymerizable liquid monomer, especially graft polymerization between thermoplastic resin particles and powder, occurs. This can be done by any device. Specifically, there are conventional extruders for thermoplastic resins and others, Banbury mixers, plastic benders, roll mills, and the like. The method that best exhibits the effects of the present invention and has high production efficiency is a method using an extruder for thermoplastic resins. It is desirable that the melt kneading be carried out for a time sufficient to convert substantially all of the polymerizable liquid monomer used into a polymer. 8 Examples Example 1 The three essential components A to C are as follows. (A) Thermoplastic resin granules: Low density polyethylene granules with MI4g/10 minute density 0.924g/cc. (Cylindrical granules of 5 mesh passes - 10 meshes) (B) Thermoplastic resin powder: The granules of (A) above were mechanically pulverized into powder of 32 mesh passes. (C) Liquid monomer: Vinyltrimethoxysilane
10 parts by weight of dicumyl peroxide dissolved in 100 parts by weight. The above (A), (B), and (C) were thoroughly mixed (650 rotations/min, 2 minutes) using a super mixer (STH-20 model manufactured by Kawada Seisakusho) as shown in Table 1, and then the inner diameter
Granulation accompanied by a graft reaction was carried out using a 400 mmφ L/D=24 vented single-screw strand cut extruder (manufactured by Thermoplastics) (set temperature: 220°C, screw rotation speed 70 rpm). Incidentally, as a measure of the heterogeneity of the reaction, fissure eye (locally crosslinked insoluble material) was measured. The measurement method is to create a 0.5 mmt press sheet after granulation, and use a small biaxial stretching machine (set temperature 160
The stretched sheet was stretched by a factor of 1.5 at 100° C.), and the number of fisheyes having a diameter of 0.1 mm or more in the stretched sheet was measured. In addition, the vinylsilane-modified polyethylene obtained in this example is used as a coating material for electric wires, etc., and in that case, it is intended to be crosslinked with moisture, so it was crosslinked as shown in Table 1, and the Physical properties were measured. As shown in Table 1, the present invention, which uses a mixture of granules and powders as the thermoplastic resin, is more uniform than the conventional method, and has improved crosslinking degree and tensile strength/strength in terms of quality after crosslinking. A stable graft product with significantly improved strength was obtained.

[Table] Example 2 The three essential components A to C are as follows. (A) Thermoplastic resin granules: high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), polypropylene (PP), and ethylene-propylene copolymer (EPP) (B) Thermoplastic resin powder :HDPE, PP, EPP,
and low density polyethylene (LDPE) (C) Liquid monomer: Hydrocarbon solution containing 75% by weight of acrylic acid as a monomer to be grafted and 0.5% by weight of 3,5,5-trimethylhexanoyl peroxide as a reaction initiator. (A), (B), and (C) were mixed as shown in Table 2 in a super mixer in the same manner as in Example 1 (650 rpm, 2 minutes). Next, the inner diameter is 40mmφ,
Granulation accompanied by a graft reaction was carried out using a vented single-screw strand cut type extruder with L/D=24.

[Table] Example-1 as a measure of reaction heterogeneity
The hue of the pellets obtained by granulation (JIS Z
6730) was measured. In addition, the acrylic acid-modified polyolefin obtained in this example is intended for adhesion to stone, iron, polyamide, etc. as a coating agent or adhesive, so the adhesive strength with iron was increased by the following method. It was measured. Press sheets of each acrylic acid grafted polyolefin obtained as above (thickness: 0.1 mm)
After degreasing and cleaning the surface with hexane, it was sandwiched between two iron plates (SS-41, thickness 1.6 mm) and pressed for 3 minutes at 200℃ and 40Kg/ ^cm2 , and then tested for tensile shear strength. was measured (ASTM D-1002
−64, tensile speed 50mm/mm). The results are shown in Table-2.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A method for producing a modified resin, which comprises melt-kneading a mixture containing the following components A, B, and C under polymerization conditions for component C to polymerize component C. A Thermoplastic resin granules that passed through 4 meshes of JIS standard sieves but not 12 meshes, B Thermoplastic resin powders that passed 20 meshes of JIS standard sieves, C Polymerizable liquid monomer. However, the weight ratio of these three components is as follows. A/B=99/1~80/20 C/A+B=0.1/100~10/100