Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition including: a grafted polymer including a diene-based rubber polymer grafted with a (meth)acrylate-based monomer unit and a vinyl aromatic monomer unit; a non-grafted polymer including a (meth)acrylate-based monomer unit and a vinyl aromatic monomer unit; and 3 to 30 wt% of waste artificial marble.

Description

[Technical Field]

[0001] Cross-reference to related applications

[0002] This invention claims priority based on Korean Patent Application No. 10-2021-0066306, dated May 24, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This invention relates to a thermoplastic resin composition, and more specifically, to a thermoplastic resin composition having excellent scratch resistance and impact resistance. [Background Technology]

[0005] More and more countries are taking measures to address global environmental pollution, such as marine pollution caused by plastics, and there is a trend towards seeking various methods for recycling waste plastics. South Korea is no exception to this global trend. Recently, the refusal to collect recyclable resources, raised as a social issue, also seems to be related to this global trend from a broader perspective. Against this backdrop, the waste plastics generated after the introduction or improvement of systems that can minimize waste plastics will need to be recycled. Therefore, research on biodegradable and renewable plastics has been actively conducted by domestic companies.

[0006] From this perspective, artificial marble is a building material that has recently attracted much attention, with a global production of approximately 300,000 tons and a market of about 600 billion Korean won. Domestic production in South Korea is 100,000 tons. Currently, the artificial marble used in South Korea is made from (meth)acrylate monomers, (meth)acrylate polymers, and fillers. However, the manufacturing process of processing artificial marble into the required sizes generates a large amount of debris and dust, which cannot be used for other products and is simply dumped in landfills or incinerated, causing soil pollution. Therefore, research is underway on methods to utilize waste artificial marble.

[0007] [Existing Technical Documents]

[0008] [Patent Literature]

[0009] (Patent Document 1) KR2009-0092882A [Summary of the Invention]

[0010] [Technical Issues]

[0011] One object of the present invention is to provide a thermoplastic resin composition with excellent scratch resistance and impact resistance.

[0012] [Technical Solution]

[0013] In order to solve the above problems, (1) the present invention provides a thermoplastic resin composition comprising: a grafted polymer comprising a diene rubber polymer grafted with (meth)acrylate monomer units and vinyl aromatic monomer units; a non-grafted polymer comprising (meth)acrylate monomer units and vinyl aromatic monomer units; and 3 to 30% by weight of waste artificial marble.

[0014] In addition, (2) the present invention provides a thermoplastic resin composition as described in (1), wherein the waste artificial marble contains (meth)acrylate monomer units.

[0015] In addition, (3) the present invention provides a thermoplastic resin composition as described in (1) or (2) comprising 10 to 30% by weight of the waste artificial marble.

[0016] Furthermore, (4) the present invention provides a thermoplastic resin composition as described in any one of (1) to (3), comprising 10 to 50% by weight of the grafted polymer.

[0017] Furthermore, (5) the present invention provides a thermoplastic resin composition as described in any one of (1) to (4), wherein a vinyl cyanide monomer unit is grafted onto the diene rubber polymer.

[0018] Furthermore, (6) the present invention provides a thermoplastic resin composition as described in any one of (1) to (5), wherein the grafted polymer comprises a free polymer not grafted onto the diene rubber polymer, the free polymer comprising (meth)acrylate monomer units and vinyl aromatic monomer units.

[0019] Furthermore, (7) the present invention provides a thermoplastic resin composition as described in any one of (1) to (6), wherein the diene rubber polymer has an average particle size of 200 to 500 nm.

[0020] Furthermore, (8) the present invention provides a thermoplastic resin composition as described in any one of (1) to (7) comprising 30 to 80% by weight of the ungrafted polymer.

[0021] Furthermore, (9) the present invention provides a thermoplastic resin composition as described in any one of (1) to (8), wherein the ungrafted polymer comprises vinyl cyanide monomer units.

[0022] In addition, (10) the present invention provides a thermoplastic resin composition as described in any one of (1) to (9), comprising: 5 to 20 wt% of the diene rubber polymer; 20 to 70 wt% of the (meth)acrylate monomer unit; 10 to 30 wt% of the vinyl aromatic monomer unit; and 3 to 30 wt% of the waste artificial marble.

[0023] [Invention Effects]

[0024] The thermoplastic resin composition of the present invention achieves excellent scratch resistance and impact resistance. [Detailed Implementation]

[0025] The invention will be described in more detail below to aid in understanding it.

[0026] At this point, the terms or words used in the specification and claims should not be interpreted as limited to their conventional or dictionary meanings. Rather, they should be interpreted as meanings and concepts consistent with the technical concept of the invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best interpret his invention.

[0027] In this invention, "diene rubber polymer" can refer to a polymer prepared by crosslinking only a diene monomer or by crosslinking a diene monomer and a comonomer that can copolymerize with it. The diene monomer can be one or more selected from the group consisting of 1,3-butadiene, isoprene, chloroprene, and isoprene, with 1,3-butadiene being preferred. The comonomer can include aromatic vinyl monomers, vinyl cyanide monomers, and olefin monomers. The diene rubber polymer can be one or more selected from the group consisting of butadiene rubber polymers, butadiene-styrene rubber polymers, butadiene-acrylonitrile rubber polymers, and ethylene-propylene rubber polymers.

[0028] In this invention, the "(meth)acrylate monomer" can be (meth)acrylate C1-C 10 Alkyl ester monomers, and (meth)acrylic acid C1-C 10 The alkyl ester monomer can be one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate and decyl methacrylate, with methyl methacrylate being preferred.

[0029] In this invention, the "vinyl aromatic monomer" may be one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene and p-methylstyrene, wherein styrene is preferred.

[0030] In this invention, the “vinyl cyanide monomer” may be one or more selected from the group consisting of acrylonitrile, methacrylonitrile, phenyl acrylonitrile and α-chloroacrylonitrile, wherein acrylonitrile is preferred.

[0031] In this invention, "average particle size" can refer to the arithmetic mean particle size in the particle size distribution measured by dynamic light scattering, specifically the average particle size of the scattering intensity. The average particle size can be measured using a Nicomp 370HPL device (product name, manufacturer: PSS Nicomp).

[0032] 1. Thermoplastic resin composition

[0033] The thermoplastic resin composition according to embodiments of the present invention comprises: a grafted polymer comprising a diene rubber polymer grafted with (meth)acrylate monomer units and vinyl aromatic monomer units; a non-grafted polymer comprising (meth)acrylate monomer units and vinyl aromatic monomer units; and 3 to 30% by weight of waste artificial marble.

[0034] Generally, artificial marble can be created with various textures, colors, and patterns, thus offering excellent decorative effects. It is easy to polish and precision machine, and possesses excellent chemical resistance, stain resistance, heat resistance, workability, and impact resistance. It is also easy to maintain and suitable for various applications. However, when artificial marble is processed into building and kitchen materials, approximately 15 to 20% waste artificial marble, such as scraps and dust, is generated. This waste artificial marble can be pyrolyzed and used as raw material, or crushed and recycled as raw material for artificial marble production.

[0035] However, the inventors discovered that when waste artificial marble is used in an appropriate amount in a thermoplastic resin composition, scratch resistance can be significantly improved while minimizing the reduction in impact resistance, and the resulting composition has excellent processability and can be applied to a wide range of fields, thus completing the present invention.

[0036] The thermoplastic resin composition according to embodiments of the present invention may contain 3 to 30% by weight of waste artificial marble, preferably 10 to 30% by weight. When the content is below the above conditions, the improvement in scratch resistance cannot be achieved. When the content exceeds the above conditions, processability decreases and injection molding becomes impossible.

[0037] The thermoplastic resin composition may contain 10 to 50% by weight of grafted polymer, preferably 20 to 40% by weight. When the above conditions are met, a thermoplastic resin composition with excellent impact resistance can be prepared.

[0038] The thermoplastic resin composition may contain 30 to 80% by weight of ungrafted polymer, preferably 35 to 70% by weight. When the above conditions are met, a thermoplastic resin composition with excellent processability can be prepared.

[0039] Meanwhile, the thermoplastic resin composition may contain 5 to 20% by weight of diene rubber polymer, preferably 10 to 15% by weight. When the above conditions are met, the impact resistance and surface gloss of the thermoplastic resin composition can be improved.

[0040] Furthermore, the thermoplastic resin composition may contain 20 to 70% by weight of (meth)acrylate monomer units, preferably 30 to 50% by weight. When the above conditions are met, the impact resistance and processability of the thermoplastic resin composition can be improved.

[0041] Furthermore, the thermoplastic resin composition may contain 10 to 30% by weight of vinyl aromatic monomer units, preferably 15 to 30% by weight. When the above conditions are met, the processability of the thermoplastic resin composition can be improved.

[0042] In addition, the thermoplastic resin composition may contain 3 to 30% by weight of waste artificial marble, preferably 10 to 30% by weight. When the above conditions are met, scratch resistance can be improved while minimizing the reduction in impact resistance of the thermoplastic resin composition.

[0043] The components of the present invention will be described in detail below.

[0044] 1) Grafted polymers

[0045] Graft polymers are components that improve the impact resistance of thermoplastic resin compositions. Graft polymers comprise diene rubber polymers grafted with (meth)acrylate monomer units and vinyl aromatic monomer units, and also comprise free polymers containing (meth)acrylate monomer units and vinyl aromatic monomer units that are not grafted onto the diene rubber polymer.

[0046] Meanwhile, the graft polymer may contain 20 to 70% by weight of a diene rubber polymer, preferably 30 to 60% by weight. When the above conditions are met, (meth)acrylate monomer units and vinyl aromatic monomers are grafted onto the diene rubber polymer at appropriate levels, thereby preparing a graft polymer with excellent impact resistance and excellent surface gloss.

[0047] Furthermore, the average particle size of the diene rubber polymer can be 200 to 500 nm, preferably 250 to 400 nm. When the above conditions are met, graft polymers with excellent impact resistance and surface gloss can be prepared.

[0048] The graft polymer may contain 20 to 60% by weight, preferably 30 to 50% by weight, of (meth)acrylate monomer units. When the above conditions are met, it exhibits excellent compatibility not only with the ungrafted polymer but also with the waste artificial marble described later, enabling the preparation of graft polymers that maximize the improvement in scratch resistance and impact resistance (which are the effects of waste artificial marble).

[0049] The graft polymer may contain 3 to 30% by weight of vinyl aromatic monomer units, preferably 5 to 20% by weight. When the above conditions are met, a graft polymer with improved processability can be prepared.

[0050] Simultaneously, (meth)acrylate monomer units, vinyl aromatic monomer units, and vinyl cyanide monomers can be grafted onto diene rubber polymers. In this case, the grafted polymer can contain less than 7% by weight of vinyl cyanide monomer units. When the above conditions are met, grafted polymers with improved chemical resistance can be prepared while minimizing yellowing. Furthermore, the formation of solids (agglomerates) can be minimized during the preparation of the grafted polymer.

[0051] Grafted polymers can be prepared by emulsion polymerization, suspension polymerization and bulk polymerization, but emulsion polymerization, which can produce grafted polymers with both excellent impact resistance and surface gloss, is preferred.

[0052] 2) Non-grafted polymers

[0053] Ungrafted polymers are components that improve the processability of thermoplastic resin compositions. Ungrafted polymers contain (meth)acrylate monomer units and vinyl aromatic monomer units.

[0054] The ungrafted polymer may contain 60 to 85% by weight, preferably 65 to 80% by weight, of (meth)acrylate monomer units. When the above conditions are met, it exhibits excellent compatibility not only with the grafted polymer but also with the waste artificial marble described later, enabling the preparation of ungrafted polymers that maximize the improvement in scratch resistance and impact resistance (which are the effects of waste artificial marble).

[0055] The ungrafted polymer may contain 15 to 40% by weight of vinyl aromatic monomer units, preferably 20 to 35% by weight. When the above conditions are met, an ungrafted polymer with excellent processability can be prepared.

[0056] Non-grafted polymers may also contain vinyl cyanide monomers to improve chemical resistance. In this case, to minimize yellowing, it is preferable to contain less than 20% by weight.

[0057] Ungrafted polymers can be prepared by one or more methods selected from the group consisting of emulsion polymerization, suspension polymerization and bulk polymerization, with bulk polymerization being preferred for preparation of high-purity polymers.

[0058] 3) Waste artificial marble

[0059] It contains waste artificial marble to improve the scratch resistance of thermoplastic resin compositions.

[0060] Since waste artificial marble is a byproduct of artificial marble production, it can be manufactured using the same methods. Specifically, as artificial marble, a composition for artificial marble can be used, comprising (meth)acrylate monomers, (meth)acrylate polymers, initiators, and fillers as raw materials. The composition for artificial marble can then be manufactured by extrusion, compression molding and curing, followed by demolding and post-processing. Here, post-processing can refer to cooling, grinding, or sanding.

[0061] The (meth)acrylate polymer used as a component of the composition for artificial marble may be polymethyl methacrylate. The initiator may be one or more selected from the group consisting of tert-butyl perbenzoate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexanoate, and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane. The filler may be one or more selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium carbonate, silica, alumina, and potassium aluminate.

[0062] Since the main raw materials of waste artificial marble are (meth)acrylate monomers and (meth)acrylate polymers, waste artificial marble can contain (meth)acrylate monomer units. Furthermore, due to the (meth)acrylate monomer units contained in waste artificial marble, the aforementioned grafted and ungrafted polymers exhibit excellent compatibility. As a result, the scratch resistance of the thermoplastic resin composition can be significantly improved, while minimizing the reduction in impact resistance.

[0063] Waste artificial marble can be one or more of the group consisting of scrap and dust generated during the processing of artificial marble, or it can be pre-crushed processed products. However, if it is waste artificial marble, it can be used regardless of its shape, so there are no particular limitations. Furthermore, even when using scrap larger than dust, due to the raw material characteristics of waste artificial marble, the compatibility between grafted and ungrafted polymers is excellent, thus significantly improving the scratch resistance of the thermoplastic resin composition. In addition, considering the ease of processing the thermoplastic resin composition, the waste artificial marble is preferably less than 2 mm in size and preferably in powder form. Waste artificial marble with the desired particle size can be obtained using a sieve.

[0064] The embodiments of the present invention will be described in detail below to enable those skilled in the art to readily implement the invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0065] Preparation Example 1

[0066] Prepare a mixed solution comprising 100 parts by weight of deionized water, 1.0 parts by weight of sodium dodecylbenzenesulfonate, 35 parts by weight of methyl methacrylate, 11.9 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.5 parts by weight of tert-dodecyl mercaptan, 0.048 parts by weight of sodium formaldehyde sulfoxylate, 0.015 parts by weight of disodium ethylenediaminetetraacetate, 0.001 parts by weight of ferrous(II) sulfate and 0.04 parts by weight of cumene hydroperoxide.

[0067] 50 parts by weight of butadiene rubber polymer latex (average particle size of rubber polymer in latex: 250 nm, gel content: 90%) were added to a reactor, and the reactor temperature was raised to 75°C. Polymerization was carried out for 3 hours with the mixed solution continuously introduced into the reactor. Then, the reactor temperature was raised to 80°C, and polymerization was terminated after 1 hour of curing to obtain grafted polymer latex.

[0068] The grafted polymer latex was placed in an aqueous solution containing 2 parts by weight of magnesium acetate and 0.5 parts by weight of formic acid, and agglomerated by mechanical shearing (mechanical agglomeration). Then, it was cured, washed, dehydrated and dried to obtain grafted polymer powder.

[0069] Preparation Example 2

[0070] A feedstock obtained by mixing 68 parts by weight of methyl methacrylate, 22 parts by weight of styrene, 7 parts by weight of acrylonitrile, 3 parts by weight of methacrylic acid, 30 parts by weight of toluene, and 0.15 parts by weight of tert-dodecyl mercaptan was continuously introduced into a reactor to achieve an average residence time of 3 hours, and polymerization was carried out. The reactor temperature was maintained at 148°C. The polymerization solution continuously discharged from the reactor was heated in a preheating tank, and unreacted monomers were volatilized in a volatilization tank. Then, while maintaining the polymerization solution temperature at 210°C, ungrafted polymer granules were prepared using a polymer delivery pump extruder.

[0071] Preparation Example 3

[0072] The waste artificial marble is recycled by recovering the fragments and dust generated during the commercialization of artificial marble prepared by extrusion, compression molding and post-processing of a composition for artificial marble containing polymethyl methacrylate, methyl methacrylate, tert-butyl peroxide, ethylene glycol dimethacrylate, 2-(methacryloyloxy)ethyl phosphate and aluminum hydroxide, resulting in powdered waste artificial marble.

[0073] Examples 1 to 5

[0074] Thermoplastic resin compositions were prepared by mixing the grafted polymer of Preparation Example 1, the ungrafted polymer of Preparation Example 2, and the waste artificial marble of Preparation Example 3 in the amounts shown in Table 1 below.

[0075] Comparative Examples 1 to 5

[0076] Thermoplastic resin compositions were prepared by mixing the grafted polymer of Preparation Example 1, the ungrafted polymer of Preparation Example 2, and the waste artificial marble of Preparation Example 3 in the amounts shown in Table 2 below.

[0077] Comparative Example 6

[0078] The following amounts, as shown in Table 2, are mixed to prepare a thermoplastic resin composition comprising a butadiene rubber polymer grafted with styrene and acrylonitrile and having an average particle size of 250 nm, a grafted polymer (ABS, manufacturer: LG Chem Co., Ltd., trade name: DP270), a styrene / acrylonitrile polymer (SAN, manufacturer: LG Chem Co., Ltd., trade name: 92HR), and the waste artificial marble powder of Preparation Example 3.

[0079] Comparative Example 7

[0080] The following amounts, as shown in Table 2, are mixed to prepare a thermoplastic resin composition comprising a butadiene rubber polymer grafted with styrene and acrylonitrile and having an average particle size of 250 nm (ABS, manufacturer: LG Chem Co., Ltd., trade name: DP270) and a styrene / acrylonitrile polymer (SAN, manufacturer: LG Chem Co., Ltd., trade name: 92HR).

[0081] Experimental Example 1

[0082] Samples were prepared by extrusion and injection molding after mixing 100 parts by weight of the thermoplastic resin composition of the examples and comparative examples, 0.5 parts by weight of (N,N'-ethylenedi(stearamide)) as a lubricant, and 0.3 parts by weight of an antioxidant. The physical properties of the samples were evaluated by the following methods, and the results are shown in Tables 1 and 2 below.

[0083] (1) Pencil Hardness: According to ASTM D3363, after placing the surface of a 10cm×10cm×3mm sample at 23°C and 50% relative humidity for 48 hours, it is scratched 5 times with pencils of various hardnesses at 23°C under a load of 500g. The degree of scratching is visually evaluated. When more than two pencil scratch marks appear on the sample surface, the pencil hardness is classified as follows.

[0084] (Soft) 6B-5B-4B-3B-2B-B-HB-FH-2H-3H-4H-5H-6H (Hard)

[0085] (2) Impact strength of cantilever beam (kgf·cm / cm, 1 / 4In): It is measured at 25°C according to ASTM D256-10.

[0086] [Table 1]

[0087]

[0088] [Table 2]

[0089]

[0090] Referring to Tables 1 and 2, Examples 1 to 5, which contain a suitable amount of waste artificial marble, exhibit excellent scratch resistance and impact resistance. However, Comparative Example 1, which does not contain waste artificial marble, does not exhibit excellent scratch resistance. Furthermore, the scratch resistance of Comparative Examples 2 and 3, which contain a small amount of waste artificial marble, is not improved compared to Comparative Example 1.

[0091] Furthermore, in Comparative Examples 4 and 5, which contained excessive amounts of waste artificial marble, injection could not be performed, and therefore samples could not be prepared.

[0092] Furthermore, compared to Comparative Example 7, which did not contain waste artificial marble, Comparative Example 6, which contained diene graft polymers and waste artificial marble, improved scratch resistance, but the improvement was not significant. Moreover, even in Comparative Example 6, which contained the same amount of waste artificial marble as in Example 3, the improvement in scratch resistance was insufficient due to reduced compatibility.

Claims

1. A thermoplastic resin composition comprising: Grafted polymers comprising diene rubber polymers grafted with (meth)acrylate monomer units and vinyl aromatic monomer units; Non-grafted polymers containing (meth)acrylate monomer units and vinyl aromatic monomer units; and 3 to 30% by weight of waste artificial marble.

2. The thermoplastic resin composition of claim 1, wherein, The waste artificial marble contains (meth)acrylate monomer units.

3. The thermoplastic resin composition of claim 1, comprising 10 to 30% by weight of the waste artificial marble.

4. The thermoplastic resin composition of claim 1, comprising 10 to 50% by weight of the grafted polymer.

5. The thermoplastic resin composition of claim 1, wherein, Vinyl cyanide monomer units are grafted onto the diene-based rubber polymer.

6. The thermoplastic resin composition of claim 1, wherein, The grafted polymer comprises a free polymer not grafted onto the diene rubber polymer, the free polymer comprising (meth)acrylate monomer units and vinyl aromatic monomer units.

7. The thermoplastic resin composition of claim 1, wherein, The diene-based rubber polymer has an average particle size of 200 to 500 nm.

8. The thermoplastic resin composition of claim 1, comprising 30 to 80% by weight of the ungrafted polymer.

9. The thermoplastic resin composition of claim 1, wherein, The ungrafted polymer contains vinyl cyanide monomer units.

10. The thermoplastic resin composition of claim 1, wherein, The thermoplastic resin composition comprises: 5 to 20% by weight of the diene rubber polymer; 20 to 70% by weight of the (meth)acrylate monomer units; 10 to 30% by weight of the vinyl aromatic monomer units, and 3 to 30% by weight of the aforementioned waste artificial marble.

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