JPH0267359A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition of improved mechanical strengths and moldability by mixing a polyamide resin with another thermoplastic resin and a specified graft polymer. CONSTITUTION:100pts.wt. total of 5-95wt.% polyamide resin (A) and 95-5wt.% thermoplastic resins (B) other than component A (e.g., PS) is mixed with 0.3-30 pts.wt. graft polymer (C) of a number-average MW of 5000-300000, composed of a branch component comprising monomer units of an unsaturated carboxylic acid which may be esterified with an aliphatic tert. alcohol and a trunk component comprising polymer segments of good compatibility with component B.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention provides a polyamide resin composition that can be used in a wide range of applications such as general consumption and industrial molding materials, synthetic fibers, and adhesives. More specifically, the present invention relates to a polyamide resin composition that utilizes a polymer alloy technique, which has recently attracted attention as a modification method when modifying the polyamide by blending different types of polymers.

[Prior art and its problems]

Polyamide has excellent toughness, self-lubricating properties, wear resistance,
Because it has properties such as chemical resistance, self-extinguishing properties, and gas barrier properties, it is used as an engineering plastic in a wide range of fields such as automobiles, electrical and mechanical parts, and packaging materials.

However, polyamide itself has problems such as dimensional changes due to moisture absorption and impact strength at low temperatures, and in order to improve these points, many proposals have been made, such as blending hydrophobic polymers with polyamide.

The resins to be blended with the polyamide include acrylonitrile-butadiene-styrene terpolymer, acrylonitrile-styrene copolymer, polyolefin, polystyrene, polyester, polyphenylene oxide, carboxyl-modified polybutadiene, maleic anhydride-modified polyolefin, nitrile rubber, and other species. Resins such as polyamide have been proposed.

In all of the above proposals, the main technical problem is how to uniformly mix the polyamide and each of the above resins, which are not compatible with each other, and as a means to solve this problem, carboxyl groups etc. Attempts have been made to mix the above-mentioned resin and polyamide in a two-component system, or to mix them in a three-component system using a compatibilizer.

Normally, when attempting to modify polyamide with a two-component blend, the carboxyl groups in the resin into which carboxyl groups have been introduced, which are mixed with the polyamide, tend to react with the polyamide to form a polymer with a high molecular weight. ,
There was a problem in that the moldability of the resulting resin composition deteriorated.

In addition, a proposal regarding a three-component blend using a compatibilizer is a proposal to add an ethylene-acrylic acid copolymer metal salt to a polyamide/polypropylene blend (JP-A-56-167740 and JP-A-56-167751, etc.), a proposal to use a styrene-methacrylic acid copolymer in combination with a polyamide/polystyrene blend [Journal of Applied Polymer Science (J, Appl, Polym.
Sci, ), 18.965 (1974)) and a proposal to use a styrene-maleic anhydride copolymer or a styrene-maleimide copolymer together with a polyamide/poly-7-enylene oxide blend (JP-A-57-1999). 36
No. 150, JP-A-59-27942 and JP-A-59
27945), but the molded bodies obtained from the resin compositions proposed by these proposals had problems in mechanical strength.

In the proposal for the three-component blend mentioned above, each random copolymer used as a compatibilizer has good compatibility with polyamide due to the effect of polar groups such as carboxyl groups, but it is difficult to incorporate into the polyamide phase. As a result, it is presumed that the effect of being present at the interface between the polyamide and the other resin and contributing to the intimate mixing of the two cannot be fully expressed.

It is well known in the fishing industry that propolymers or graft polymers having blocks of polymer segments of different types are effective as compatibilizers for resin compositions, as opposed to random copolymers. The present inventors have discovered that the terminal (
Graft polymers obtained by polymerizing polymers having polymerizable groups such as meth)acryloyl groups with other monomers (hereinafter referred to as graft polymers produced by the macromonomer method) are used in blends of polyamides and other thermoplastic resins. A proposal has been made regarding a resin composition used as a compatibilizer (Japanese Unexamined Patent Publication No. 164760/1983). The graft polymer in this proposal has a structure in which the backbone polymer has carboxyl groups that have an affinity with polyamide, while the cane polymer has monomer units that are compatible with the thermoplastic resin blended with the polyamide. [This is a graft polymer formed, and the polyamide resin composition obtained using the graft polymer with such a structure has significantly improved mechanical strength compared to conventional polyamide resin compositions. However, since the melt viscosity of the resulting resin composition is high, there is still room for improvement in terms of moldability.

(B) Structure of the Invention [Means for Solving the Problems] As a result of intensive studies in view of the above-mentioned problems of the prior art, the present inventors have discovered that carboxyl groups that have an affinity for polyamides or Compatibilization in a polyamide resin composition of a graft polymer by a macromonomer method, in which an unsaturated carboxylic acid monomer unit esterified with an aliphatic tertiary alcohol capable of producing the carboxyl group is introduced into a branch polymer. As a result of using it as an agent,
The present inventors have discovered that the miscibility of the resin composite acid can be improved without causing an increase in melt viscosity, and a molded article with excellent mechanical strength can be obtained, and the present invention has been completed.

That is, the present invention provides a polyamide resin composition comprising a polyamide, a thermoplastic resin other than polyamide, and a graft polymer obtained by a macromonomer method, wherein the branch components of the graft polymer are esterified with an aliphatic tertiary alcohol. The present invention is a polyamide-based resin composition having unsaturated carboxylic acid monomer units, which may or may not be present, and whose main component is a polymer segment having good compatibility with the thermoplastic resin other than polyamide.

The present invention will be explained in more detail below.

〔polyamide〕

The polyamide used in the present invention is a polymer formed by a condensation reaction of a diamine and a dibasic acid, a self-condensation reaction of an amino acid, or a ring-opening polymerization reaction of a lactam, and is generally referred to collectively as "nylon". .

Polyamides useful in the present invention have bonds within the backbone of the following formula: Specifically, polyhexamethylene adipamide (nylon-6), polycaprolactam (nylon-6), polyundecanolactam (nylon-11), polycaprylactam (nylon-12),
Polyhexamethylene sebamide (nylon-(S, 10
), polypyrrolidone (nylon-4), polyhebutlactam (nylon-7), polycaprilactam (nylon-8), polycaprylactam (nylon-9), polyhexamethylene azelainamide (nylon-9), Polyhexamethylene isophthalamide, polymethaxylylene adipamide, polyamide of hexamethylene diamine and n-dodecanedioic acid (nylon-6,12), polyamide of dodecamethylene diamine and n-dodecanedioic acid (nylon 12.12), and these Examples include copolymers of

Furthermore, a copolymer obtained by block copolymerizing the above-mentioned polyamide with polyether, polyester, polyimide, vinyl polymer, etc. can also be used.

Polycaprolactam (nylon-6) and polyhexamethylene adipamide (nylon-6,6) are preferably used.

Polyamide can be produced by any known method (usually, it can be produced by equimolar polycondensation reaction of diamine and dicarboxylic acid, self-polycondensation reaction of aminocarboxylic acid, or ring-opening polymerization of lactam).

[Thermoplastic resin other than polyamide]

In the polyamide resin composition of the present invention, various resins used as general plastic molding materials can be used as the thermoplastic resin which is the main component along with the polyamide.

Specifically, polystyrene, high impact polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene terpolymer (generally A
It is called BSIM fat. Hereinafter referred to as ABS resin, L AB
Each cover resin in which the rubber component of S resin is replaced with acrylic rubber, chlorinated polyethylene or ethylene-propylene-diene monomer terpolymer (generally referred to as diene rubber), polymethyl methacrylate, polyvinyl chloride,
Examples include polyphenylene oxide, polycarbonate and polysulfone, with polystyrene, polyphenylene oxide and ABS resin being preferred. The above thermoplastic resins can be used alone or in combination of two or more.

The preferred blending ratio of the polyamide and thermoplastic resin is:
Weight ratio of polyamide/thermoplastic resin = 5/95 to 951
5, more preferably 20/80 to 80/
The range is 20.

If the proportion of the minor component is less than 5%, the physical properties of the minor component will not be sufficiently reflected in the resin composition, which is not preferable.

[Graft polymer]

In the present invention, the graft polymer used as a compatibilizer in a blend of polyamide and a Q thermoplastic resin other than polyamide is a graft polymer produced by the macromonomer method, and has aliphatic groups in the branch components derived from the macromonomer, as described above. It is a graft polymer that has unsaturated carboxylic acid monomer units that may or may not be esterified with a tertiary alcohol, and whose backbone component is a polymer segment that is highly compatible with thermoplastic resins other than polyamide.

In a graft polymer having a monomer unit having the above-mentioned ester bond in a branch component, the ester bond is hydrolyzed by heating in the cross-linking step for preparing a polyamide resin composition. Functions as a compatibilizer when converted into a group-containing one.

Carboxyl groups with or without esterification with aliphatic tertiary alcohols are referred to below as polyamide-friendly structures.

The macromonomer used as a raw material for the synthesis of the above-mentioned graft polymer is such that the polymer skeleton thereof is a simple form of an unsaturated carboxylic acid such as (meth)acrylic acid, maleic acid, and fumaric acid, and/or a (meth)amic acid of an aliphatic tertiary alcohol. A polymer consisting of acrylic acid ester monomers, or copolymerizable monomers with these monomers, such as (meth)acrylic esters of styrene, aliphatic primary or secondary alcohols, and There are polymers consisting of (meth)acrylonitrile, etc., and macromonomers having a radically polymerizable group such as a (meth)acryloyl group at one end of these polymers are preferable, and more preferably, the polymer skeleton has an affinity for polyamide. The structure is an aliphatic tertiary alcohol (
It is a macromonomer with a polyamide affinity structure derived from meth)acrylic acid ester. A macromonomer having a carboxyl group as a polyamide-affinity structure tends to contain impurities during its manufacturing process.

The molecular weight of the macromonomer is 500 to 2 in number average molecular weight.
0,000 is preferable, and 1,000 to 15,000 are more preferable. If the average molecular weight is 500 or less, the molecular weight is too low, and the graft polymer approaches a random copolymer (therefore, the anchoring effect on the thermoplastic resin decreases.If the number average molecular weight is 20,000 or more, the graft polymer is not added. The melt viscosity of the resulting resin composition increases, leading to a decrease in moldability.

The number average molecular weight of the above macromonomer is determined by gel permeation chromatography (hereinafter referred to as GPC).
This is the molecular weight in terms of polystyrene.

To explain an example of a method for producing a macromonomer, for example, 1-butyl methacrylate is radically polymerized in the presence of a chain transfer agent having a carboxyl group in the molecule to produce polymethacrylic acid t-butyl having a carboxyl group at one end. Butyl is synthesized, and then the poly t-butyl methacrylate and a vinyl polymerizable monomer having a glycidyl group in the molecule are reacted in the presence of a catalyst such as a tertiary amine or quaternary ammonium salt to produce methacrylate. It is like producing a macromonomer of t-butyl acid.

As the chain transfer agent having a carboxyl group in the molecule, a mercaptan compound having an appropriate chain transfer constant, such as mercaptoacetic acid, 6-mercaptopropionic acid, 2-mercaptopropionic acid, etc., is preferably used.

Further, as the vinyl polymerizable monomer having a glycidyl group in the molecule, glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, etc. are used, and glycidyl methacrylate is preferred.

The monomer that is copolymerized with the macromonomer to constitute the backbone component of the graft polymer is a monomer that, by radical polymerization, provides a polymer that is highly compatible with the thermoplastic resin to be blended with the polyamide. Such monomers include vinyl esters of organic acids such as vinyl acetate, styrene, styrene substituted products,
Examples include vinylnaphthalene, alkyl (meth)acrylate, and (meth)acrylonitrile, with styrene, alkyl (meth)acrylate, and acrylonitrile being preferred. By appropriately selecting these monomers and copolymerizing them alone or in combination with a macromonomer, a polymer segment having good compatibility with the thermoplastic resin used is formed as a backbone component of the graft polymer. be able to.

Examples of combinations of thermoplastic resins and corresponding trunk segments include the following.

1) Polystyrene, high impact polystyrene, polyphenylene oxide → polystyrene l) Acrylonitrile-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin, polycarbonate → acrylonitrile-styrene copolymer or polymethyl methacrylate 111) Methacrylic resin, Polyvinyl chloride → polymethyl methacrylate or acrylonitrile-styrene copolymer The graft polymer in the present invention has the above-described trunk and branch components in the molecule, and the weight composition of both the trunk and branch components is as follows: It is preferable that the number of branch components is 2 to 80, and it is more preferable that the number of branch components is 2 to 5096. If the number of branch components is less than 2, the compatibilizing effect is likely to be insufficient when the graft polymer is melt-kneaded as a compatibilizer for polyamide and thermoplastic resin. moldability is likely to be impaired.

In the present invention, the content of monomer units that provide a polyamide-affinity structure in the graft polymer is preferably 1 to 60% by weight based on the total amount of all monomers forming the graft polymer, More preferably 3 to 20% by weight. If it is less than 1% by weight, almost no reaction with the polyamide will occur and it will be difficult to find a compatibilizing effect.If it exceeds 30% by weight, the viscosity of the polyamide will be more dominant than the compatibilizing effect and moldability will tend to deteriorate.

In addition, the molecular weight of the graft polymer is 50 in number average molecular weight.
00 to 500,000 is preferable. Number average molecular weight is 500
If it is less than 0, the molecular chain length of the backbone component is too short, and no significant compatibilizing effect can be expected (on the other hand, if it is more than 300,000, the rate of melting and diffusion into polyamides and other thermoplastic resins is slow, and crosstalk takes a long time.

Copolymerization of the macromonomer and other monomers can be carried out by - a solution polymerization method using a radical polymerization initiator, which is carried out in boat fishing;
This can be carried out by a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, or the like.

The preferred amount of the graft polymer to be used when preparing the polyamide resin composition of the present invention is selected within the range of 0.3 to 30 parts by weight based on the total of 100 parts by weight of the polyamide and thermoplastic resin, and more preferably It is selected in a range of 1 to 20 parts by weight. If the amount of the graft polymer added is less than α3 parts by weight, the compatibilizing effect will be insufficient, so it is not preferable (,'
If it exceeds 30 parts by weight, it is not preferable because the kneading melt viscosity may increase, resulting in a decrease in moldability or a decrease in the physical properties of the final molded product.

The graft polymer having a carboxyl group esterified with an aliphatic tertiary alcohol in its branch component as a polyamide-miscible structure may be used as a polyamide-miscible structure if desired.
Part or all of the ester bond with alcohol
K may be added to the polyamide resin composition after being converted into a carboxyl group by a known hydrolysis method using an acid catalyst or heating.

Next, a method for preparing a polyamide resin composition will be explained.

The preparation of the polyamide resin composition in the present invention uses the king of polyamides, thermoplastic resins and graft polymers.
Melt kneading may be carried out using a conventional pre-mixing method, such as an extruder, a niegu, or an open roll.

The blending order of these champions is: - Blend method, blending the polyamide and graft polymer first, then blending the thermoplastic resin, blending the thermoplastic resin and the graft polymer first, then blending the Examples include a method of blending polyamide.

When using a graft polymer having a carboxyl group esterified with an aliphatic 6th alcohol as a branch component, it is necessary to decompose the ester bond due to the 6th alcohol and convert it into a carboxyl group during melt blending. Therefore, the blending temperature is preferably 220°C or higher, more preferably 240°C or higher.

At temperatures below 220°C, the decomposition reaction of ester bonds does not proceed sufficiently, making it difficult to achieve a compatibilizing effect.

The polyamide resin composition of the present invention also contains various additives commonly used in plastic molded articles, such as plasticizers, antioxidants, stabilizers, inorganic fillers, reinforcing agents such as glass fiber, pigments, A dye and an elastomer component such as a modified product of an unsaturated acid anhydride such as a butadiene elastomer or an olefin elastomer can be added as appropriate.

The present invention will be explained in more detail by referring to Reference Examples, Comparative Reference Examples, Examples, and Comparative Examples below.

Incidentally, "chi" written on each side means "weight" and "1 part" means parts by weight.

Reference Example 1: Production of Macromonomer Into a glass flask equipped with a stirrer, reflux condenser, dropping funnel, gas introduction pipe and thermometer, 50 parts of t-butyl methacrylate, 607 parts of mercaptoacetic acid, and 50 parts of toluene were added.
of t-butyl methacrylate into the dropping funnel.
00 parts of toluene, 100 parts of toluene, and 1.5 parts of azobisisobutyronitrile (hereinafter abbreviated as AIBN) were added. The temperature of the internal solution was set at 90° C. by heating the flask, and the solution in the dropping funnel was added dropwise over 3 hours. The reaction was further continued for 4 hours to obtain a carboxyl-terminated prepolymer. To this solution, 10 parts of glycidyl methacrylate, 1.5 parts of quaternary ammonium salt, and 06 parts of hydroquinone monomethyl ether α were added, and 9 parts of glycidyl methacrylate was added under air bubbling.
The reaction was carried out at 0°C for 8 hours. The reaction conversion rate determined from the acid value was 98.5 LII. The solvent was removed by vacuum drying to obtain 140 parts of a solid t-butyl methacrylate skeleton macromonomer. The average molecular weight of this product in terms of polystyrene by GPC is: M1m=310, MW=
It was 6700.

Reference Example 2: Production of Gra7 Toborimer A Into a glass flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer, 400 parts of distilled water and a 5ts aqueous solution of polyvinyl alcohol (Popal 420 manufactured by Kuraray ■) were added.
10 parts of calcium phosphate suspension (Supertite 10, manufactured by Nihon Kagaku Kogyo ■), 0.0 parts of a 5% aqueous solution of sodium silbenzenesulfonate (Emar 2F, manufactured by Kao ■).
I prepared the second part. A solution containing 10 parts of the macromonomer produced in Reference Example 1, 90 parts of methyl methacrylate, 0.4 parts of n-dodecyl nuccabutaf, and 5 parts of AIBNα was added dropwise. Heat the flask to raise the temperature of the internal liquid to 8.
After setting the temperature to 0°C, the solution in the dropping funnel was added dropwise over 1 minute.

The temperature was maintained at 80°C for 7 hours to complete the polymerization reaction.

After the reaction, the mixture was filtered and dried under reduced pressure to obtain 91 parts of solid graft polymer A. The average molecular weight in terms of polystyrene by GPC is Mfl=100,000Mw=550,00
It was 0.

Reference Example 3; Production of Graft Polymer B As a monomer component, 10% of the macromonomer of Reference Example 1 was used.
parts, using 90 parts of styrene, n −.

Graft polymer B was obtained in the same manner as in Reference Example 2, except that dodecyl mercaptan was not used and 1.0 part of AIBN was used. The average molecular weight in terms of polystyrene by GPC is Mn = 4 s, o 00MW = 230,00
It was 0.

Comparative Reference Example 1: Production of Graft Polymer ○ As monomer components, 30 parts of a polymethyl methacrylate macromonomer having a methacrylic group at the end (macromonomer AA-6 manufactured by Toagosei Chemical Co., Ltd.), 60 parts of methyl methacrylate, and methacrylate were used. except that 10 parts of acid, 1 part of n-dodecyl mercaptan and 0.5 parts of AIBN are used.
Graft polymer 〇 was obtained in the same manner as in Reference Example 2. G
The average molecular weight in terms of polystyrene by PC is Mn=2
tOOOMw=45,000.

Comparative Reference Example 2: Production of Graft Polymer D As a monomer component, a polystyrene macromonomer having a methacrylic group at the end (macromonomer AS manufactured by Toagosei Kagaku Kogyo ■) was used as a monomer component.
-6), 50 parts of methyl methacrylate, 10 parts of styrene, 10 parts of methacrylic acid, 1 part of n-dodecylmercaptan, and 0.5 parts of AIBN, but the same as Reference Example 2. Graft polymer D was obtained by the method described above. The average molecular weight in terms of polystyrene by GPC is Mn
=14,000 Mr=52,000.

Example 1 and Comparative Examples 1 and 2 Commercially available nylon-6 (Nylon 101!IB manufactured by Ube Industries)
), 40 parts of a commercially available ABS resin (Mitsubishi Mo/Santo ■Tough, Kusu TFX-461), and the graft polymer shown in Table 1 were tri-blended, and a twin screw extruder (caliber 29■L/D) was prepared. =25) at a resin temperature of 260
Melt blended at °C. Melt flow index of the obtained resin composition (according to JIS K7210-1976, measured under 2.169 load and 240°C)
, tensile test (the pellet was press-formed and then machined to create a test piece, and the tensile speed was 10·■/min in accordance with JIS K7113-1981), Charpy impact test (the pellet was press-formed and then machined). Test pieces were prepared by processing and evaluated according to JIS K7111-1977 (with and without notches). The results are shown in Table 1.

Examples 2-3 and Comparative Examples 5-5 Commercially available nylon-6 (Nylon 1015B manufactured by Ube Industries)
60 parts, 40 parts of a commercially available polyphenylene oxide resin (Noryl 534J manufactured by Engineering Plastic ■), and the graft polymer shown in Table 2 were triblended,
Twin screw extruder (diameter 29mm L/D=25)
The mixture was melt-blended at a resin temperature of 270°C. Melt flow index of the resulting resin composition (2.16 mm load 275°C), tensile test (test specimens were prepared by press molding and machining the pellets, and the tensile speed was 10 m31/min), Charpy Impact test (test specimens were created by press molding and then machining the pellets, and conducted with a notch)
was evaluated. The results are shown in Table 2.

Table 1 (c) Effect of the invention The polyamide resin composition of the present invention using a graft polymer having a specific structure as a compatibilizer has significantly greater mechanical strength than the case where no compatibilizer is used. ■Compared to the use of conventional graft polymers (having a polyamide affinity structure in the trunk component and polymer segments compatible with thermoplastic resin in the branch components), The effect of improving the mechanical strength is the same or higher, and the melt flow index is high and the increase in melt viscosity is suppressed, so the molding processability is excellent.

Claims (1)

[Claims] 1. A polyamide-based resin composition consisting of polyamide, a thermoplastic resin other than polyamide, and a graft polymer obtained by a macromonomer method, in which branch components of the graft polymer are esterified with an aliphatic tertiary alcohol or not. 1. A polyamide resin composition having an unsaturated carboxylic acid monomer unit, the backbone component of which is a polymer segment having good compatibility with the thermoplastic resin other than polyamide.