JP2020105416A - Thermoplastic resin composition and molding - Google Patents

Abstract

To provide a thermoplastic resin composition which improves a strength such as elongation.SOLUTION: A thermoplastic resin composition contains modified polyrotaxane particles in which a resin and silica particles are coupled to each other through modified polyrotaxane.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic resin composition and a molded product.

Resin is lighter than glass, and is therefore used in various applications as a substitute for glass. In particular, styrene resins have excellent moldability and are used in applications such as automobile parts, home appliances, and packaging containers. It is also widely used for applications requiring designability. Resins used for these purposes require physical properties such as tensile strength and impact resistance.

As a method of improving the strength of the resin composition, there is a method of adding an inorganic substance such as a glass filler (Patent Document 1). However, in such a method, there is a problem in the strength of the interface between the resin and the filler, and sufficient strength may not be exhibited depending on the type of resin.

In Non-Patent Document 1, an airgel is formed by binding polyrotaxane and silica. However, even when this gel was used, there were cases where sufficient strength could not be expressed.

JP, 2017-544038, A

Lan Jiang, 4 others, "One-Pot Synthesis and Charification of Polyrotaxane-Silica Hybrid Aerogel", ACS Macro Lett. , 2017, No. 6, pp. 281-286

That is, the problem to be solved by the present invention is to provide a thermoplastic resin composition having improved strength such as elongation.

The present inventors have conducted extensive studies and experiments to solve the above problems, and found that the above problems can be solved by using modified polyrotaxane particles in which a resin and silica particles are bonded through a modified polyrotaxane. The present invention has been completed.

The present invention has the following aspects.
(1)
A thermoplastic resin composition comprising modified polyrotaxane particles in which a resin and silica particles are bonded via a modified polyrotaxane.
(2)
The thermoplastic resin composition according to (1), wherein the resin contains a monomer unit derived from an aromatic vinyl monomer.
(3)
The thermoplastic resin composition according to (1) or (2), wherein the resin contains a monomer unit derived from an alkyl (meth)acrylate.
(4)
A molded product, which is obtained by molding the thermoplastic resin composition according to any one of (1) to (3).

Since the thermoplastic resin composition of the present invention has the above constitution, it has excellent strength such as elongation.

Hereinafter, modes for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist.
The following definitions of terms apply throughout the specification and claims.
"Thermoplasticity" refers to the property of being softened by heating above the glass transition temperature or melting point, and by softening, molding processing can be easily performed.
“(Meth)acrylate” refers to at least one selected from the group consisting of acrylate and methacrylate.

Hereinafter, the present embodiment will be described in detail.
[Thermoplastic resin composition]
The thermoplastic resin composition of the present embodiment contains modified polyrotaxane particles in which a resin and silica particles are bonded via a modified polyrotaxane.

(Modified polyrotaxane particles)
-Modified polyrotaxane-
The modified polyrotaxane is a cyclic molecule of a modified polyrotaxane having a linear molecule (linear structure) penetrating the opening of a cyclic molecule (cyclic structure) and having a block group (blocking group) at both ends of the linear molecule. And is modified by reacting a functional monomer.
As the modified polyrotaxane, one having a cyclic structure that can freely move on a linear structure is preferable. The inclusion rate of the cyclic structure is preferably 50% by mass or less of the theoretical saturation value from the viewpoint that the cyclic structure easily moves freely on the linear structure.

The cyclic structure is not particularly limited, but cyclodextrin is preferable from the viewpoint of easy availability. As the cyclodextrin, α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin are preferable, and α-cyclodextrin is most preferable. The cyclodextrin may be chemically modified. It is preferable that the hydroxyl group of the cyclodextrin is modified with an isopropyl group, a caprolactone group, or the like, because phase separation with a resin that binds to the modified polyrotaxane is less likely to occur.

The cyclic structure constituting the modified polyrotaxane preferably has a group having a dicarlizable unsaturated double bond, and more preferably has a (meth)acrylate group, from the viewpoint of more strongly bonding to the silica particles and the resin. preferable. When the cyclic structure has a (meth)acrylate group, it is integrated with the monomer unit constituting the resin that binds to the modified polyrotaxane by polymerization, and the effect is easily exhibited. The cyclic structure preferably has at least two radically polymerizable groups having the unsaturated double bond.
The (meth)acrylate group may be bonded to the cyclodextrin via an isopropyl group or a caprolactone group in which the hydroxyl group of cyclodextrin is modified.

The linear structure constituting the modified polyrotaxane is not particularly limited, but one having a low glass transition temperature is preferable from the viewpoint of easily exhibiting impact resistance.
Examples of the linear structure having a low glass transition point include polyethylene glycol, polybutylene glycol, silicone resin, polybutadiene and the like. Among them, polyethylene glycol is most preferable from the viewpoint of easy availability.
The weight average molecular weight of the linear structure is preferably 5,000 to 100,000, more preferably 10,000 to 40,000. When it is at least the above lower limit, impact resistance is likely to be exhibited, and when it is at most the above upper limit, phase separation from the resin bonded to the modified polyrotaxane tends to be easily suppressed.
The weight average molecular weight of the linear structure can be measured by Gel Permeation Chromatography (GPC method).
GPC model: Tosoh HPLC-8320
Column: Shodex K-803L, K-806M
Mobile phase: Chloroform 1.0 ml/min
Sample concentration: 0.2% by mass
Temperature: oven 40°C, inlet 35°C, detector 35°C
Detector: Differential refractometer The molecular weight at each elution time was calculated from the elution curve of monodisperse polystyrene, and calculated as the molecular weight in terms of polystyrene.

The capping group that constitutes the modified polyrotaxane is a group that prevents the cyclic structure from being removed from the linear structure, and examples thereof include an adamantyl group.
The modified polyrotaxane may be used alone or in combination of two or more.

-Resin-
Examples of the monomer unit that forms the resin that binds to the modified polyrotaxane include aromatic vinyl monomers such as styrene, α-methylstyrene, paramethylstyrene, ethylstyrene, propylstyrene, butylstyrene, chlorostyrene, and bromostyrene; ) Vinyl cyanide monomers such as acrylonitrile; polyalkylenes such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate Glycol di(meth)acrylate; Polyester diol di(meth)acrylate; Polycarbonate diol di(meth)acrylate; Polyfunctional (meth)acrylate such as polyurethane di(meth)acrylate; n-butyl (meth)acrylate, isobutyl (meth) Alkyl (meth)acrylates such as acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate; polyethylene glycol mono(meth)acrylate, methoxylated polyethylene glycol mono(meth)acrylate, etc. A unit derived from a monomer component such as polyalkylene glycol mono(meth)acrylate; Among them, the ease of forming a chemical bond with the modified polyrotaxane (for example, the ease of forming a chemical bond with a radically polymerizable unsaturated double bond of the cyclic structure of the modified polyrotaxane), and the strength such as elongation From the viewpoint of superiority, aromatic vinyl monomers and monoacrylates are preferred, aromatic vinyl monomers and alkyl (meth)acrylates are more preferred, and aromatic vinyl monomers are even more preferred. These may be used alone or in combination of two or more.

The above resin preferably contains a monomer unit derived from an aromatic vinyl monomer, and from the viewpoint of further excellent strength such as elongation, the mass ratio of the monomer unit derived from an aromatic vinyl monomer is 100 parts by mass of the resin. On the other hand, it is preferably 50 parts by mass or more, and more preferably 55 to 90 parts by mass.

The resin preferably contains a monomer unit derived from an alkyl (meth)acrylate, and from the viewpoint of further excellent strength such as elongation and elastic modulus, the mass ratio of the monomer unit derived from an alkyl (meth)acrylate is The amount is preferably 50 parts by mass or less, and more preferably 10 to 45 parts by mass with respect to 100 parts by mass.

The resin is preferably a resin containing the monomer unit. The above-mentioned resin is more excellent in strength such as elongation and elastic modulus, and in the resin constituting the modified polyrotaxane particles, silica particles constituting the modified polyrotaxane particles are easily dispersed, so that the monomer unit is 300 to It is preferable to include 10000, and more preferably 500 to 5000.
The resin is preferably bound to a modified polyrotaxane, more preferably bound to a functional group of the modified polyrotaxane (for example, a group having a radically polymerizable unsaturated double bond having a cyclic structure).

When a plurality of resins are bonded to the modified polyrotaxane, each resin may be the same or different. In addition, the resins may have different weight average molecular weights.

-Silica particles-
The silica particles preferably have a functional group that forms a chemical bond with the modified polyrotaxane (for example, a radically polymerizable unsaturated double bond having a cyclic structure) on the surface.
In particular, a thiol group or a (meth)acrylate group is preferable because it is easy to react with a (meth)acrylate group. The fact that the silica particles and the modified polyrotaxane form a chemical bond can be confirmed by conducting a surface analysis of the silica particles by XPS or IR.
The silica particles are preferably bonded to the modified polyrotaxane, and more preferably bonded to a functional group of the modified polyrotaxane (for example, a group having a radically polymerizable unsaturated double bond having a cyclic structure).

When a plurality of silica particles are bonded to the modified polyrotaxane, each silica particle may be the same or different.

-Method for producing modified polyrotaxane particles-
The method for producing the modified polyrotaxane particles, for example, a method of reacting the silica particles and the modified polyrotaxane to form modified polyrotaxane-modified silica particles, a method of reacting the monomer component and the modified polyrotaxane-modified silica particles, and the like. Can be mentioned.

In the production of the modified polyrotaxane-modified silica particles, the addition amount of the silica particles is preferably 2 to 20 parts by mass based on 100 parts by mass of the total mass of the silica particles and the modified polyrotaxane.
A solvent or the like may be added in the production of the modified polyrotaxane-modified silica particles.
The modified polyrotaxane-modified silica particles can be obtained by, for example, a method of stirring at 10 to 80° C. (for example, room temperature) for 1 hour to 50 hours. The modified polyrotaxane-modified silica particles obtained may be purified by filtration or the like, or may be dried by vacuum drying or the like.

In the production of the modified polyrotaxane particles, a polymerization initiator such as a thermal polymerization initiator and a solvent may be added in addition to the modified polyrotaxane-modified silica particles and the monomer component.
Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,2). 4-dimethylvaleronitrile) and other azo-based polymerization initiators; 1,1-bis(t-butylperoxy)cyclohexane and other peroxyketals; di-t-butylperoxide, 2,5-dimethyl-2, Dialkyl peroxides such as 5-di(t-butylperoxy)hexane; diacyl peroxides such as benzoyl peroxide and m-toluoyl peroxide; peroxyesters such as dimyristyl peroxydicarbonate; cyclohexanone per Ketone peroxides such as oxides; Hydroperoxides such as p-mentor hydroperoxide; 2,2-bis(4,4-ditertiarybutylperoxycyclohexyl)propane, 2,2-bis(4,4-) Difunctional tertiary amylperoxycyclohexyl)propane, 2,2-bis(4,4-ditertiarybutylperoxycyclohexyl)butane, 2,2-bis(4,4-dicumylperoxycyclohexyl)propane Oxides; and the like. Among them, the azo-based polymerization initiator is preferable, and 2,2′-azobisisobutyronitrile is more preferable, from the viewpoint that the modified polyrotaxane particles having a uniform molecular weight can be efficiently polymerized and can be easily obtained.
The addition amount of the polymerization initiator is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to the total mass (100 parts by mass) of the monomer component and the modified polyrotaxane-modified silica particles. ~5 parts by mass. If the addition amount of the polymerization initiator is equal to or more than the lower limit value, the polymerization is likely to proceed, and if the addition amount is equal to or less than the upper limit value, the strength of the copolymer resin obtained by the polymerization without forming gel or the like tends to be more excellent. is there.
The modified polyrotaxane particles can be obtained, for example, by a method of polymerizing at a temperature of 50 to 150° C. for 3 to 100 hours.

The content of the modified polyrotaxane particles in the thermoplastic resin composition of the present embodiment is 0.1 parts by mass with respect to 100 parts by mass of the thermoplastic resin composition from the viewpoint of further excellent physical strength such as elongation. The amount is preferably the above, more preferably 0.5 to 20 parts by mass, and further preferably 2 to 10 parts by mass.

In the thermoplastic resin composition of the present embodiment, the modified polyrotaxane particles are present in a form in which the silica particles forming the modified polyrotaxane particles are dispersed in the resin forming the modified polyrotaxane particles.

(Other ingredients)
The thermoplastic resin composition of this embodiment may further contain other components.
Other components include, for example, lubricants, plasticizers, release agents, antibacterial agents, antifungal agents, light stabilizers, ultraviolet absorbers, bluing agents, dyes, pigments, antistatic agents, heat stabilizers, defoamers. , A dispersant and the like.

The content of other components is preferably 3 parts by mass or less, and more preferably 1 part by mass or less, based on the total mass (100 parts by mass) of the modified polyrotaxane particles. The smaller the content of the other components, the easier it is for the resulting molded article to exhibit good properties.

The silica particles are contained in the thermoplastic resin composition in an amount of 0.1 to 20 parts by mass, preferably 1 to 15 parts by mass, more preferably 2 to 10 parts by mass. When it is at least the above lower limit value, the tensile strength is improved, and when it is at most the above upper limit value, elongation does not decrease.

The thermoplastic resin composition of the present embodiment can be obtained by mixing the modified polyrotaxane particles described above with other components as necessary.

[Molded body]
The molded body of this embodiment is a molded body obtained by molding the thermoplastic resin composition of the above-described embodiment.
The molded body can be obtained, for example, by a method of kneading the thermoplastic resin composition and molding the same.
The molded product can be used, for example, as a vehicle interior component, a home electric appliance housing, a food packaging container, or the like.

(Action effect)
The molded article of the present embodiment shows an improvement in tensile strength while maintaining elongation by dispersing the phase composed of the modified polyrotaxane particles in which the resin and the silica particles are chemically bonded via the modified polyrotaxane, in the matrix.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

The evaluation methods used in each of the examples described below are shown below.
<Evaluation method>
(Tensile test)
ISO37 type2 A dumbbell test piece having a thickness of 2 mm was used to perform a tensile test under the following conditions.
Model: INSTRON 5564
Tensile speed: 5mm/min
Distance between chucks: 25mm
The strain and maximum stress at break of the test piece were read.

(XPS)
The modified polyrotaxane-modified silica particles were analyzed by the following method.
Model: ULVAC-PHI Co., Ltd. Versa probeII
Excitation source: mono. AlKα 20kV×5mA 100W
Analysis size: 100μm×1.4mm
Photoelectron take-off angle: 45°
Capture area: Survey scan 0 to 1,100 eV
Narrow scan, C 1s, S 2p, Si 2p, O 1s, N 1s
Pass Energy: Survey scan 117.4 eV
Narrow scan: 46.95 eV

<Example 1>
2.5 g of thiol-modified silica particles (R-cat-Sil MP manufactured by Kanto Kagaku Co., Ltd.) were weighed in a glass bottle and subjected to nitrogen substitution. As a modified polyrotaxane, 9 g of Celm (registered trademark) superpolymer SA1313P (manufactured by Advanced Soft Materials Co., Ltd., hereinafter "SA1313P") was dissolved in 56 ml of toluene and added to a glass bottle using a syringe. Furthermore, 0.5 ml of amylamine (manufactured by Tokyo Kasei Co., Ltd., purity>98.0%) was added to a glass bottle, and after stirring for 10 hours, a solid was obtained by suction filtration, and vacuum drying was performed to obtain modified polyrotaxane-modified silica particles. I got it. The obtained modified polyrotaxane-modified silica particles were analyzed by XPS, and it was confirmed that the vicinity of the surface of the silica particles was modified with the modified polyrotaxane.
1 g of the obtained modified polyrotaxane-modified silica particles is weighed in a glass bottle, 180 ml of styrene, 20 ml of ethylbenzene, and 0.5 g of 2,2′-azobisisobutyronitrile are added, and the mixture is added at 80° C. for 8 hours and 110° C. for 4 hours. By heating at 130° C. for 4 hours, a thermoplastic resin composition solution was obtained in which the silica particles in the particles in which silica particles and polystyrene were bonded to the modified polyrotaxane were dispersed in the polystyrene matrix.
After reprecipitating the obtained solution in ethanol, it was vacuum dried and recovered to obtain a thermoplastic resin composition.

(Production of molded body)
The thermoplastic resin composition was kneaded in a kneader (Xplore MC15, manufactured by Rheo Lab Co., Ltd.) at 220° C. under a nitrogen atmosphere by rotating a screw at 100 rpm for 5 minutes. After kneading, the molten resin was poured into a mold of ISO37 type 2 held at 30° C. and held for 40 seconds to obtain a small test piece. A tensile test was performed using this test piece.

<Example 2>
A thermoplastic resin composition and a small test piece were obtained in the same manner as in Example 1, except that 120 ml of styrene and 80 ml of n-butyl acrylate (Tokyo Kasei Co., Ltd.) were used as monomers and kneading was performed at 160°C. Then, a tensile test was performed.

<Comparative Example 1>
A thermoplastic resin composition and a small test piece were obtained in the same manner as in Example 1 except that the resin was polymerized without using silica particles, and the same amount of thiol-modified silica particles was added during kneading, and a tensile test was performed.

Types of monomer units used in Examples 1 and 2 and Comparative Example 1, content of silica particles, modified polyrotaxane-modified silica particles (Comparative Example 1 is unmodified silica particles) XPS measurement results, tensile test of molded test pieces The results are shown in Table 1. The content of the monomer unit is a mass ratio with respect to 100 parts by mass of the total amount of the added monomer components.

From Examples 1 and 2, when the resin and silica particles are bonded via the modified polyrotaxane, both tensile elongation and breaking stress are improved.

Claims (4)

A thermoplastic resin composition comprising modified polyrotaxane particles in which a resin and silica particles are bonded via a modified polyrotaxane. The thermoplastic resin composition according to claim 1, wherein the resin contains a monomer unit derived from an aromatic vinyl monomer. The thermoplastic resin composition according to claim 1, wherein the resin contains a monomer unit derived from an alkyl (meth)acrylate. A molded product obtained by molding the thermoplastic resin composition according to any one of claims 1 to 3.