Polypropylene resin composition

Abstract

The present invention provides a material that can balance fire resistance, flame blocking property, and good fluidity that makes the formability excellent, while being able to tolerate long-time flame contact. A propylene resin composition characterized by containing a polypropylene resin (A) that satisfies requirement (A1), a flame retardant (B) that satisfies requirement (B1), and a fiber (C) that satisfies requirement (C1), and satisfies condition 1 and condition 2.

Description

Technical Field

[0001] This invention relates to polypropylene resin compositions. More specifically, it relates to polypropylene resin compositions containing phosphorus-based flame retardants and glass fibers that exhibit excellent fire resistance and flame-blocking properties. Background Technology

[0002] Polyolefin resins, with their superior chemical and mechanical properties, have been widely used in various fields such as building materials, automotive parts, packaging materials, and home appliances, and their applications are gradually expanding. However, many polyolefin resins are flammable and require flame retardancy depending on the application. Previously, a widely used flame retardant method was a system combining brominated flame retardants with antimony trioxide as a flame retardant additive.

[0003] However, flame retardant methods using brominated flame retardants lack shape retention when the material softens due to heat, making them difficult to withstand prolonged flame contact due to their material properties. In contrast, flame retardant methods using phosphorus-based flame retardants, especially those that form charred residue after combustion, maintain their shape through carbonization of the flame contact surface, thus exhibiting fire resistance and flame-blocking properties, and are expected to withstand longer periods of flame contact.

[0004] On the other hand, in the case of materials using phosphorus-based flame retardants, such as those represented by Patent Document 1 and Patent Document 2, although most studies have been conducted on self-extinguishing properties such as oxygen index and UL94 V test, there are few examples of in-depth studies on fire resistance and flame blocking properties. It is hoped that materials with the fire resistance and flame blocking properties required by society have been clearly identified.

[0005] In addition, a study in Patent Document 3 has been reported in recent years, in which the fire resistance of a test piece made by combining a phosphorus-based flame retardant with glass fiber was studied.

[0006] However, the flame contact time used in the evaluation of the technology disclosed in Patent Document 3 cannot be considered sufficient. For example, the Chinese standard GB / T 38031-2020 adopts the following standard: assuming an EV vehicle fire occurs, "in the battery pack state, after the battery catches fire, no smoke / fire is generated outside the battery pack within 5 minutes." However, the invention in Patent Document 3 completely fails to consider fire resistance performance beyond 5 minutes, and does not discuss materials with fire resistance and flame-blocking properties that are practically required in society. In other words, the problem of providing materials with the performance required by future society to withstand prolonged flame contact remains.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2003-026935

[0010] Patent Document 2: Japanese Patent Application Publication No. 2011-088970

[0011] Patent Document 3: International Publication No. 2020-071420 Summary of the Invention

[0012] The problem the invention aims to solve

[0013] The objective of this invention is to provide a material that can balance fire resistance, flame blocking properties, and good flowability for long-term flame exposure, as well as excellent formability, for material systems composed of phosphorus-based flame retardants combined with glass fiber and polypropylene that are troubled by the above-mentioned problems.

[0014] Solution for solving the problem

[0015] In order to solve the above-mentioned problems, the present invention has conducted repeated and in-depth research and found that by blending flame retardants and fibers in a specific ratio into polypropylene resins, and thereby optimizing the melt flow rate (hereinafter, sometimes simply referred to as MFR) of the resin portion relative to the amount of flame retardant, the resulting polypropylene resin composition can solve the above-mentioned problems. Based on these insights, the present invention was completed.

[0016] That is, the present invention has the following structure. [1]

[0018] A propylene resin composition, characterized in that it contains a polypropylene resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and a fiber (C) satisfying the following requirement (C1), and satisfies conditions 1 and 2 below.

[0019] Requirements (A1)

[0020] The polypropylene resin (A) comprises at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers and propylene block copolymers.

[0021] Requirements (B1)

[0022] Flame retardant (B) is an organic flame retardant.

[0023] Requirements (C1)

[0024] Fiber (C) is glass fiber.

[0025] Condition 1

[0026] The propylene resin composition contains 24-65% by weight of polypropylene resin (A), 5-26% by weight of flame retardant (B), and 30-50% by weight of fiber (C) (wherein, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight).

[0027] Condition 2

[0028] The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (wherein the total of the polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below.

[0029] (Condition 2-1)

[0030] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 75g / 10min or less.

[0031] (Condition 2-2)

[0032] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 18% by weight or more and 26% by weight or less, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 105g / 10min or less. [2]

[0034] According to the propylene resin composition of [1], wherein the polypropylene resin (A) further satisfies the following requirement (A2).

[0035] Requirement (A2)

[0036] The polypropylene resin (A) includes at least two types: polypropylene resin (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16kg load) of the polypropylene resin (Aa) is in the range of 60~2000 / 10 minutes. [3]

[0038] According to the acrylic resin composition of [1] or [2], wherein the fiber (C) further satisfies the following requirement (C2).

[0039] Requirements (C2)

[0040] As fiber (C), glass fiber with a fiber length of 1~20mm is used. [4]

[0042] The propylene resin composition according to any one of [1] to [3], wherein the flame retardant (B) is a phosphorus-based flame retardant. [5]

[0044] According to the acrylic resin composition described in [4], the flame retardant (B) is a polyphosphate. [6]

[0046] A molded article obtained from any one of the acrylic resin compositions described in [1] to [5].

[0047] The effects of the invention

[0048] According to the present invention, a material can be provided that can simultaneously achieve fire resistance that can withstand prolonged flame contact, flame blocking properties, and good flowability that enables excellent formability. Detailed Implementation

[0049] The present invention is an acrylic resin composition, characterized in that it contains a polypropylene resin (A) satisfying the following requirement (A1), a flame retardant (B) satisfying the following requirement (B1), and a fiber (C) satisfying the following requirement (C1), and satisfies the following conditions 1 and 2.

[0050] Requirements (A1)

[0051] The polypropylene resin (A) comprises at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers and propylene block copolymers.

[0052] Requirements (B1)

[0053] Flame retardant (B) is an organic flame retardant.

[0054] Requirements (C1)

[0055] Fiber (C) is glass fiber.

[0056] Condition 1

[0057] The propylene resin composition contains 24-65% by weight of polypropylene resin (A), 5-26% by weight of flame retardant (B), and 30-50% by weight of fiber (C) (wherein, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight).

[0058] Condition 2

[0059] The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (wherein the total of the polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below.

[0060] (Condition 2-1)

[0061] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 75g / 10min or less.

[0062] (Condition 2-2)

[0063] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 18% by weight or more and 26% by weight or less, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 105g / 10min or less.

[0064] The details of each item of the acrylic resin composition of the present invention are described below.

[0065] 1. Acrylic resin composition

[0066] The acrylic resin composition of the present invention satisfies the following condition 1.

[0067] Condition 1

[0068] The acrylic resin composition contains 24-65% by weight of polypropylene resin (A), 5-26% by weight of flame retardant (B), and 30-50% by weight of fiber (C) (wherein, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Details of the polypropylene resin (A), flame retardant (B), and fiber (C) are described later.

[0069] The acrylic resin composition needs to contain 24-65% by weight of polypropylene resin (A), preferably 29-59% by weight, more preferably 34-54% by weight, and even more preferably 40-49% by weight. The flame retardant (B) must contain 5-26% by weight, preferably 10-25% by weight, more preferably 14-24% by weight, and even more preferably 18-23% by weight. The fiber (C) must contain 30-50% by weight, preferably 31-46% by weight, more preferably 32-42% by weight, and even more preferably 33-38% by weight.

[0070] By setting the contents of polypropylene resin (A), flame retardant (B), and fiber (C) within such a range, a material can be provided that can withstand prolonged flame exposure, provide flame barrier properties, and offer excellent flowability for formability.

[0071] The acrylic resin composition of the present invention also satisfies the following condition 2.

[0072] Condition 2

[0073] The melt flow rate (MFR, 230°C, 2.16 kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (wherein the total of the polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below.

[0074] (Condition 2-1)

[0075] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 75g / 10min or less.

[0076] (Condition 2-2)

[0077] The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 18% by weight or more and 26% by weight or less, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 105g / 10min or less.

[0078] Generally, when the melt flow rate of polypropylene resin (A) is low, the material exhibits excellent shape retention when softened by heat such as from contact with flames. Even with a low content of flame retardant (B), it tends to have good fire resistance and flame-blocking properties. On the other hand, even when the melt flow rate of polypropylene resin (A) is high, if the content of flame retardant (B) is high, in addition to the flame-retardant effect brought by flame retardant (B), the melt flow rate of the mixture of polypropylene resin (A) and flame retardant (B) also decreases. Therefore, by increasing the content of flame retardant (B), shape retention can be improved, resulting in good fire resistance and flame-blocking properties.

[0079] In this invention, in the region where the content of flame retardant (B) is low, i.e., in the region where the content of flame retardant (B) specified in (condition 2-1) is 5% by weight or more and less than 18% by weight (where the total of polypropylene resin (A), flame retardant (B), and fiber (C) is set to 100% by weight), sufficient fire resistance and sufficient flame blocking properties can be exhibited by setting the melt flow rate of polypropylene resin (A) to 75 g / 10 min or less. Here, when the melt flow rate of polypropylene resin (A) exceeds 75 g / 10 min, sufficient shape retention is not obtained, and sometimes it is difficult to exhibit sufficient fire resistance and sufficient flame blocking properties. Within this range, the melt flow rate is preferably 74 g / 10 min or less, more preferably 73 g / 10 min or less, more preferably 72 g / 10 min or less, particularly preferably 71 g / 10 min or less, and especially preferably 70 g / 10 min or less.

[0080] Furthermore, in regions with a high content of flame retardant (B), specifically where the content of flame retardant (B) specified in (Condition 2-2) is 18% to 26% by weight (where the total of polypropylene resin (A), flame retardant (B), and fiber (C) is set at 100% by weight), good fire resistance and flame-blocking properties can be obtained even if the melt flow rate of polypropylene resin (A) exceeds 75 g / 10 min, as long as it is below 105 g / 10 min. However, even in regions with a high content of flame retardant (B) (Condition 2-2), sufficient fire resistance and flame-blocking properties are sometimes not exhibited when the melt flow rate of polypropylene resin (A) exceeds 105 g / 10 min. Within this range, the melt flow rate is preferably 104 g / 10 min or less, more preferably 103 g / 10 min or less, more preferably 102 g / 10 min or less, particularly preferably 101 g / 10 min or less, and especially preferably 100 g / 10 min or less.

[0081] In either (Condition 2-1) or (Condition 2-2), the lower limit of the melt flow rate of the polypropylene resin (A) is typically 0.5 g / 10 min, preferably 0.8 g / 10 min, more preferably 1.0 g / 10 min, and even more preferably 1.5 g / 10 min. By setting the lower limit of the melt flow rate of the polypropylene resin (A) within such a range, sufficient shape retention, sufficient fire resistance, sufficient flame-blocking properties, and good formability can be obtained. That is, when the lower limit of the melt flow rate of the polypropylene resin (A) is lower than the above range, the possibility of deterioration in formability increases.

[0082] (1) Polypropylene resin (A)

[0083] The following is a detailed description of the polypropylene resin (A) used in this invention.

[0084] Requirements (A1)

[0085] The polypropylene resin (A) used in this invention comprises at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers and propylene block copolymers.

[0086] As a propylene random copolymer, a propylene-α-olefin random copolymer is preferred. Furthermore, as a propylene block copolymer, a propylene-α-olefin block copolymer is preferred. Hereinafter, in this specification, propylene-α-olefin block copolymers and propylene-α-olefin random copolymers will sometimes be simply referred to as "propylene-α-olefin copolymers".

[0087] The preferred propylene-α-olefin copolymer is a copolymer of propylene and an α-olefin with 2 to 8 carbon atoms (excluding propylene) as comonomers, with a propylene content of 70 to 99.99% by weight (i.e., a comonomer content of 0.01 to 30% by weight), and more preferably a random copolymer or block copolymer of propylene and α-olefin with a propylene content of 90% by weight or more. Alternatively, it may be a mixture of different random copolymers or block copolymers of α-olefins.

[0088] In addition, one type of comonomer of α-olefins with 2 to 8 carbons other than propylene can be used as the copolymerization monomer with propylene, or two or more types can be used in combination.

[0089] Specifically, examples of propylene-α-olefin copolymers include binary copolymers such as propylene-ethylene copolymers, propylene-butene-1 copolymers, propylene-pentene-1 copolymers, propylene-hexene-1 copolymers, and propylene-octene-1 copolymers; terpolymers such as propylene-ethylene-butene-1 copolymers and propylene-ethylene-hexene-1 copolymers; and preferably, propylene-ethylene random copolymers and propylene-ethylene-butene-1 random copolymers. The content of α-olefin monomers in the propylene-α-olefin copolymer typically ranges from about 0.01% to 30% by weight, preferably 1% to 20% by weight, and more preferably about 1% to 10% by weight.

[0090] Examples of α-olefins with 2 to 8 carbon atoms other than propylene include ethylene, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, and 1-octene.

[0091] Furthermore, from a formability viewpoint, the melting point of the polypropylene resin (A) is preferably 100–170°C, more preferably 150–165°C. The melting point of the polypropylene resin can be appropriately adjusted based on the types of propylene and α-olefins other than propylene used as raw materials, the copolymerization ratio, and the melt flow rate (MFR). It should be noted that the term "melting point" in this specification refers to the melting peak temperature measured by a differential scanning calorimeter (DSC).

[0092] The polypropylene resin (A) used in this invention needs to satisfy either condition 2-1 or condition 2-2 according to JIS K7210 [test temperature 230°C, load 2.16 kg (21.18 N)]. Therefore, it is generally preferred to be 0.5 to 105 g / 10 min, 1.0 to 100 g / 10 min, more preferably 5.0 to 90 g / 10 min, and even more preferably 10 to 75 g / 10 min. By setting the melt flow rate (MFR) within such a range, good flame retardant properties, i.e., fire resistance, flame blocking properties, and formability, can be maintained in the propylene resin composition of this invention and the molded articles formed therefrom, and good damage resistance and flexural strength are also exhibited. That is, if the melt flow rate (MFR) is less than 0.5 g / 10 min, the load during molding of the acrylic resin composition of the present invention will increase, the formability will deteriorate, and discoloration of the molded body will occur, and the appearance may deteriorate. Conversely, if it exceeds 105 g / 10 min, the damage resistance and flexural strength may be impaired, and sufficient shape retention may not be obtained. Therefore, sufficient fire resistance and sufficient flame blocking properties may not be obtained.

[0093] It should be noted that when the polypropylene resin (A) contains two or more propylene polymers, each of these two or more propylene polymers may have a melt flow rate (MFR) within the above-mentioned range, or a portion or all of the two or more propylene polymers may have a melt flow rate (MFR) outside the above-mentioned range, but the polypropylene resin (A) as a whole has a melt flow rate (MFR) within the above-mentioned range.

[0094] Furthermore, in this invention, the polypropylene resin (A) preferably uses a polypropylene resin with an isotactic pentamerous group percentage (mmmm percentage) of 96% or more, which indicates its crystallinity; more preferably, the isotactic pentamerous group percentage is 97% or more. When the isotactic pentamerous group percentage is 96% or more, damage resistance and flexural strength become good, and therefore it is preferred. This is an effect resulting from the orientation of crystals on the surface of the molded body in the polypropylene resin (A). The crystallinity of the polypropylene resin (A) can be controlled by adjusting the copolymerization ratio of the raw materials and the molecular weight distribution using the catalyst.

[0095] In addition, the percentage (mmmm) of the above-mentioned five-unit group is using 13 The values ​​measured by C-NMR (nuclear magnetic resonance) are obtained using nuclear magnetic resonance spectroscopy based on isotopic carbon. 13 The isotactic percentage of pentagonal units in a polypropylene molecular chain, determined by C-NMR. That is, the isotactic pentagonal percentage is the percentage of propylene units formed by the continuous isotactic bonding of five propylene monomer units. Specifically, it is... 13The percentage of intensity of the mmmm peak in the methyl carbon region of the C-NMR spectrum was determined using an isotactic five-unit group, for example, using a 270MHz FT-NMR apparatus manufactured by NJE Inc.

[0096] The catalyst used to obtain the polypropylene resin (A) used in this invention is not particularly limited, and known catalysts can be used. For example, so-called Ziegler-Natta catalysts that combine titanium compounds and organoaluminum (e.g., described in the Polypropylene Handbook (first edition, first printing, May 15, 1998), or metallocene catalysts (e.g., described in Japanese Patent Application Publication No. 5-295022).

[0097] The polymerization process used to obtain the polypropylene resin (A) used in this invention is not particularly limited, and known polymerization processes can be used. For example, slurry polymerization, bulk polymerization, gas-phase polymerization, etc., can be used. In addition, any of batch polymerization or continuous polymerization can be used, and multi-stage continuous polymerization such as two-stage and three-stage polymerization can be used as desired. Alternatively, it can also be manufactured by mechanically melt-blending two or more propylene polymers.

[0098] In addition, various polypropylene resins (A) that can be used as polypropylene-based resins are commercially available from many companies, such as the NOVATEC series manufactured by Nippon Polypropylene Co., Ltd. Products with the desired physical properties can also be purchased from these commercially available products for use.

[0099] The polypropylene resin (A) used in this invention preferably further satisfies the following requirement (A2).

[0100] Requirement (A2)

[0101] The polypropylene resin (A) includes at least two types: polypropylene resin (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16kg load) of the polypropylene resin (Aa) is in the range of 60~2000 / 10 minutes.

[0102] One way to implement this invention is to manufacture a masterbatch by separately blending flame retardant (B) and fiber (C) with different polypropylene resins (carrier resins), and further blending other polypropylene resins in a molding machine as needed. In this case, for the fiber masterbatch, if the melt flow rate (MFR) of the carrier resin is low, the dispersion of fiber (C) becomes poor, so a resin with a high melt flow rate (MFR) is required as the carrier resin. On the other hand, in this invention, if the melt flow rate (MFR) of the polypropylene resin (A) is too high, the fire resistance and flame blocking properties decrease, so a polypropylene resin with a low melt flow rate (MFR) is required to adjust the overall melt flow rate (MFR) of the polypropylene resin (A). Therefore, in the form of a masterbatch made by blending fiber (C) with polypropylene resins (carrier resins), at least two polypropylene resins are required. In this case, it is preferable to use another polypropylene resin as the carrier resin in the masterbatch of flame retardant (B) because the blending operation is easy.

[0103] The melt flow rate (MFR) of two or more polypropylene resins (Aa) can be the same or different, but when the melt flow rate (MFR) of (Aa) is greater than that of (Ab), it is easy to set the melt flow rate (MFR) of polypropylene resin (A) to a preferred range, and therefore preferred.

[0104] Here, the melt flow rate (MFR) of the polypropylene resin (Aa) is preferably 60 to 2000 g / 10 min, more preferably 70 to 1000 g / 10 min, even more preferably 80 to 900 g / 10 min, particularly preferably 100 to 800 g / 10 min, and most preferably 100 to 700 g / 10 min.

[0105] Furthermore, the melt flow rate (MFR) of the polypropylene resin (A) as a whole, which includes at least two types of polypropylene resin (Aa) and polypropylene resin (Ab), is the same as the melt flow rate (MFR) of the polypropylene resin (A) described above.

[0106] It should be noted that in this specification, the melt flow rate (MFR) is the value measured according to JIS K7210 at a test temperature of 230°C and a load of 2.16 kg. It should also be noted that when multiple polypropylene resins are mixed and used as polypropylene resin (A), the melt flow rate (MFR) value can be calculated, for example, using the logarithmic addition rule described in Japanese Patent No. 6331720 (for example, referring to the following formula (1)). It should be noted that (MFR... A The value represents the calculated melt flow rate of the resin section, abbreviated as MFR below. A .

[0107] log(MFR A = {(weight% of component (PP-A) × log(MFR of component (PP-A)) + (weight% of component (PP-B) × log(MFR of component (PP-B)) + (weight% of component (PP-C) × log(MFR of component (PP-C))} / 100 … Equation (1)

[0108] The types of polypropylene resins (Aa) and (Ab) (i.e., the types of propylene polymers), preferred melting points, and preferred isotactic pentad percentages are as detailed for polypropylene resin (A).

[0109] In addition, as a polypropylene resin (Ab), it may contain two or more types.

[0110] The ratio of the total content of polypropylene resin (Aa) to the total content of polypropylene resin (Ab) in polypropylene resin (A) can be arbitrarily set considering the overall melt flow rate (MFR) of polypropylene resin (A). That is, as described above, in this invention, it is important to set the melt flow rate (MFR) of polypropylene resin (A) to a desired range, and within that desired range, adjust the content of flame retardant (B) to a specific range.

[0111] (2) Flame retardant (B)

[0112] The flame retardant (B) used in this invention will now be described in detail.

[0113] Requirements (B1)

[0114] The flame retardant (B) used in this invention is an organic flame retardant.

[0115] Typically, to exhibit the desired flame retardancy, inorganic flame retardants require a larger dosage, and a higher specific gravity is needed to achieve high flame retardancy. In contrast, organic flame retardants can exhibit flame retardancy with a lower dosage, and therefore can achieve high flame retardancy with a lower specific gravity. Therefore, in this invention, an organic flame retardant is required as flame retardant (B).

[0116] There are no particular limitations on the organic flame retardants used in this invention. Various organic flame retardants such as halogen-based, phosphorus-based, and nitrogen compounds represented by guanidine-based flame retardants can be used, with phosphorus-based flame retardants being preferred.

[0117] As a phosphorus-based flame retardant, any substance commonly used as a flame retardant for polyolefins can be used. Examples include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tricyclohexyl phosphate, tri(xylene) phosphate, toluene diphenyl phosphate, xylene phenyl phosphate, dimethyl ethyl phosphate, tri(xylene) phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, hydroxyphenyl diphenyl phosphate, etc., modified with various substituents, phosphate compounds, phosphorus and nitrogen-containing phosphazene derivatives, and other compounds or mixtures thereof.

[0118] These phosphorus-based flame retardants can be used alone or in combination of two or more.

[0119] In a preferred embodiment of the invention, the phosphorus-based flame retardant is a polyphosphate. When a polyphosphate is used as an organic flame retardant, it is suitable for improving fire resistance and flame blocking properties because it forms an expanding layer during the combustion reaction.

[0120] Examples of polyphosphates include, for example, the phosphates described in

[0015] to

[0021] of Japanese Patent Application Publication No. 2003-026935 [Patent Document 1].

[0121] Alternatively, it can be used with other organic flame retardants that are not phosphorus-based, such as halogen-based or nitrogen-based flame retardants.

[0122] As halogen-based flame retardants, preferred organic halogenated aromatic compounds include, for example, halogenated diphenyl compounds, halogenated bisphenol compounds, halogenated bisphenol-bis(alkyl ether) compounds, and halogenated phthalimide compounds, with halogenated bisphenol-bis(alkyl ether) compounds being particularly preferred.

[0123] Examples of the aforementioned halodiphenyl compounds include halodiphenyl ether compounds, halodiphenyl ketone compounds, and halodiphenyl alkane compounds, with decabromodiphenylethane and other halodiphenyl alkane compounds being preferred.

[0124] Examples of the aforementioned halobisphenol compounds include halobisphenylalkanes, halobisphenyl ethers, halobisphenyl sulfides, and halobisphenyl sulfones, with bis(3,5-dibromo-4-hydroxyphenyl) sulfones and other halobisphenyl sulfides being preferred.

[0125] Examples of the aforementioned halogenated bisphenol bis(alkyl ether) compounds include (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl)methane, 1-(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-2-(3-bromo-4-2,3-dibromopropoxyphenyl)ethane, 1-(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-3-(3-bromo-4-2,3-dibromopropoxyphenyl)propane, 2,2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl)methane, 1-(3, 5-Dichloro-4-2,3-dibromopropoxyphenyl)-2-(3-chloro-4-2,3-dibromopropoxyphenyl)ethane, 1-(3,5-dichloro-4-2,3-dibromopropoxyphenyl)-3-(3-chloro-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)methane, 1,2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)ethane, 1,3-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)methane, 1,2-bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)ethane, 1,3-bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl)ethane, 1,3-bis(3,5-dichloro- 4,2,3-Dibromopropoxyphenyl)propane, 2-bis(3,5-dichloro-4,2,3-dibromopropoxyphenyl)propane, (3,5-dibromo-4,2,3-dibromopropoxyphenyl)-(3-bromo-4,2,3-dibromopropoxyphenyl) ketone, (3,5-dichloro-4,2,3-dibromopropoxyphenyl)-(3-chloro-4,2,3-dibromopropoxyphenyl) ketone, bis(3,5-dibromo-4,2,3-dibromopropoxyphenyl) ketone, bis(3,5-dichloro-4,2,3-dibromopropoxyphenyl) ketone, (3,5-dibromo-4,2,3-dibromopropoxyphenyl)-(3-bromo-4,2,3-dibromopropoxyphenyl) ether, (3,5-dichloro-4,2,3-dibromopropoxyphenyl) (3,5-dibromo-4-2,3-dibromopropoxyphenyl) ether, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) ether, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) ether, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-dibromopropoxyphenyl) sulfide, (3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl) sulfide, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) sulfide, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) sulfide, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)-(3-bromo-4-2,3-Dibromopropoxyphenyl) sulfone, (3,5-dichloro-4-2,3-dibromopropoxyphenyl)-(3-chloro-4-2,3-dibromopropoxyphenyl) sulfone, bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) sulfone, bis(3,5-dichloro-4-2,3-dibromopropoxyphenyl) sulfone, wherein bromobisphenol A (bromoaliphatic ether), bromobisphenol S (bromoaliphatic ether), chlorinated bisphenol A (chlorinated aliphatic ether), chlorinated bisphenol S (chlorinated aliphatic ether), and especially etherified tetrabromobisphenol A and etherified tetrabromobisphenol S are preferred.

[0126] Examples of etherified tetrabromobisphenol A include tetrabromobisphenol A-bis(2,3-dibromopropyl ether) and 2,2-bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl)propane. Examples of etherified tetrabromobisphenol S include bis(3,5-dibromo-4-2,3-dibromopropoxyphenyl) sulfone.

[0127] Among these halogenated flame retardants, bromine-based flame retardants have high flame retardant effects and rarely decompose even when subjected to thermal processes during the manufacture and molding of the polypropylene resin composition of the present invention, and are therefore preferred.

[0128] Examples of the aforementioned nitrogen compounds include: melamine, piperazine, N,N,N',N'-tetramethyldiaminomethane, ethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N',N'-tetramethylethylenediamine, N,N,N',N'-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, and tetramethylenediamine. Pentamethylenediamine, Hexamethylenediamine, 1,7-Diaminoheptane, 1,8-Diaminooctane, 1,9-Diaminononane, 1,10-Diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetylguanidine, benzoguanidine, guanidine acrylates, 2,4-diamino-6-nonyl-1,3,5-triazine, 2,4-diamino- 6-Hydroxy-1,3,5-triazine, 2-Amino-4,6-Dihydroxy-1,3,5-triazine, 2,4-Diamino-6-methoxy-1,3,5-triazine, 2,4-Diamino-6-ethoxy-1,3,5-triazine, 2,4-Diamino-6-propoxy-1,3,5-triazine, 2,4-Diamino-6-isopropoxy-1,3,5-triazine, 2,4-Diamino-6-mercapto-1,3,5- Triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, cyanuric acid diamide, benzoguanidine, acetylguanidine, o-phenyl diguanidine, melamine cyanurate, melamine pyrophosphate, butylidene diguanidine, norbornene diguanidine, methylene diguanidine, ethylenedi(melamine), trimethylenedi(melamine), tetramethylenedi(melamine), hexamethylenedi(melamine), 1,3-hexylidene bis(melamine), etc. Commercially available products include ADEKA STAB FP2000, FP2100, FP2200, FP2500S and ammonium polyphosphate manufactured by ADEKA Corporation.

[0129] When using phosphorus-based flame retardants in combination with various organic flame retardants such as halogenated and nitrogen compounds, the organic flame retardants can be used alone or in combination of two or more. For example, organic halogenated flame retardants and nitrogen compounds can also be used in combination with phosphorus-based flame retardants.

[0130] (3) Fiber (C)

[0131] The details of the fiber (C) used in this invention will be described below.

[0132] Requirements (C1)

[0133] Fiber (C) is glass fiber.

[0134] The fiber (C) not only improves the rigidity, impact strength and other physical properties in the acrylic resin composition and the molded articles obtained therefrom in the present invention, but also has additional properties such as improving heat resistance, dimensional stability (such as the reduction of the coefficient of linear expansion), low shrinkage, and damage resistance.

[0135] (3-1) Types and manufacturing methods of glass fiber

[0136] As described above, the fiber (C) is glass fiber. Using glass fiber as fiber (C) is preferred from the perspectives of ease of manufacture and economy of the acrylic resin composition of the present invention and the molded articles obtained therefrom.

[0137] To further enhance the effects of the present invention, the fiber (C) may be used in combination with two or more types, or it may be used in the form of a so-called masterbatch containing a high concentration in the aforementioned polypropylene resin (A) or the like.

[0138] Alternatively, non-fiber (C) fillers such as glass beads, glass spheres, mica, and various inorganic or organic fillers may be used in combination without significantly impairing the effects of the present invention.

[0139] There are no particular limitations on the type of glass used as fiber, such as E glass, C glass, A glass, S glass, etc., with E glass being the preferred choice.

[0140] There is no particular limitation on the manufacturing method of this glass fiber; it can be manufactured using various well-known manufacturing methods.

[0141] The fiber diameter of the glass fiber is preferably 3μm~25μm, more preferably 6μm~20μm.

[0142] By setting the fiber diameter of the glass fiber within a certain range, the glass fiber is less prone to breakage during the manufacture and molding of the acrylic resin composition and the molded articles obtained therefrom according to the present invention, and the aspect ratio of the fiber can be within a favorable range. Therefore, the improving effects on the rigidity and impact strength of the acrylic resin composition and the molded articles obtained therefrom can be obtained effectively. That is, when the fiber diameter is less than 3 μm, the glass fiber may be easily broken during the manufacture and molding of the acrylic resin composition and the molded articles obtained therefrom according to the present invention. On the other hand, if it exceeds 25 μm, the improving effects on the rigidity and impact strength of the acrylic resin composition and the molded articles obtained therefrom according to the present invention may decrease as the aspect ratio of the fiber decreases.

[0143] Furthermore, the glass fiber (C) preferably further satisfies the following requirement (C2).

[0144] Requirements (C2)

[0145] As fiber (C), glass fiber with a fiber length of 1~20mm is used.

[0146] The fiber length is determined by measurements taken using a microscope, vernier calipers, etc. Alternatively, when glass fiber-containing granules are obtained using methods such as pultrusion, the length of the glass fibers in these granules is substantially the same as the length of one side (extrusion direction) of the granules; therefore, the length of these granules can also be used as the glass fiber length. Furthermore, the fiber diameter is determined by measurements taken using a microscope, vernier calipers, etc.

[0147] The glass fiber can also be used in the form of so-called chopped filament glass fiber, in which the fiber filament is cut to the desired length.

[0148] When using glass fibers known as chopped strands, shorter fiber lengths facilitate processing and compounding. Therefore, 2mm to 15mm is preferred, 3mm to 10mm is more preferred, and 4mm to 8mm is even more preferred. By using glass fibers within this range, the rigidity, impact strength, and other physical properties, as well as the formability (flowability), of the acrylic resin composition and the molded articles obtained therefrom according to the present invention are all good. That is, if the fiber (C) is glass fiber and its length is less than 1mm, the rigidity, impact strength, and other physical properties of the acrylic resin composition and the molded articles obtained therefrom may decrease; on the other hand, if it exceeds 20mm, the formability (flowability) may decrease. It should be noted that the fiber length in this case can also be expressed as the length when the glass fiber is used directly as a raw material. However, in the case of glass fiber-containing granules formed by integrating multiple continuous glass fibers through melt extrusion processing as described later, this is not limited to this, and roving materials are generally used. It should be noted that two or more types of glass fibers can also be used in combination.

[0149] Glass fibers can be surface-treated or untreated. To improve dispersibility in polypropylene resin (A), glass fibers that have been surface-treated with organosilane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, organosilicon compounds, higher fatty acids, fatty acid metal salts, fatty acid esters, etc., are preferred.

[0150] Examples of organosilane coupling agents used in surface treatment include vinyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and 3-acryloyloxypropyltrimethoxysilane. Examples of titanate coupling agents include isopropyltriisostearoyl titanate, isopropyltris(dioctyl pyrophosphate) titanate, and isopropyltris(N-aminoethyl) titanate. Examples of aluminate coupling agents include aluminum acetyloxydiisopropoxide. Examples of zirconate coupling agents include tetrakis(2,2-diallyloxymethyl)butyl, di(tridecyl)zirconium phosphite, neopentyl(diallyl)oxy, and trinedecylzirconate. Examples of the aforementioned organosilicon compounds include silicone oils and silicone resins.

[0151] Furthermore, examples of higher fatty acids used for surface treatment include oleic acid, capric acid, lauric acid, palmitic acid, stearic acid, limonic acid, caleic acid, linoleic acid, rosin acid, linolenic acid, undecanoic acid, and undecenoic acid. Additionally, examples of higher fatty acid metal salts include sodium, lithium, calcium, magnesium, zinc, and aluminum salts of fatty acids with nine or more carbon atoms, such as stearic acid and limonic acid. Among these, calcium stearate, aluminum stearate, calcium limonate, and sodium limonate are suitable. Furthermore, examples of fatty acid esters include polyol fatty acid esters such as glycerol fatty acid esters, α-sulfonyl fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyethylene glycol fatty acid esters, and sucrose fatty acid esters.

[0152] There is no particular limitation on the amount of the surface treatment agent used, but it is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of glass fiber.

[0153] In addition, the glass fiber can be glass fiber that has been bundled (surface-treated) using a bundling agent. Examples of bundling agents include epoxy-based bundling agents, aromatic urethane-based bundling agents, aliphatic urethane-based bundling agents, acrylic-based bundling agents, and maleic anhydride-modified polyolefin-based bundling agents.

[0154] These bridging agents need to be melted in the melt compounding with polypropylene resin (A), therefore bridging agents that melt at temperatures below 200°C are preferred.

[0155] Specific examples of so-called short-cut filament glass fibers include Nippon Electric Glass Co., Ltd. (T480H), etc.

[0156] Alternatively, these glass fibers can also be used as follows: a granule formed by pre-processing a continuous plurality of glass fibers with an arbitrary amount of, for example, polypropylene resin (A) through melt extrusion using a method such as pultrusion, and wherein the length of the glass fibers in the granule is substantially the same as the length of one side (extrusion direction) of the granule, is more preferred from the perspective of further improving the rigidity, impact strength, and other physical properties of the acrylic resin composition of the present invention and the molded articles formed therefrom. In this case, "substantially" specifically means that, based on the total number of glass fibers in the glass fiber-containing granule, at least 50%, preferably at least 90%, of the length is the same as the length (extrusion direction) of the glass fiber-containing granule, and the fibers are hardly damaged during the preparation of the granule.

[0157] There are no particular limitations on the manufacturing method of such glass fiber granules. For example, when using a resin extruder, multiple glass fibers are continuously drawn from a fiber support through a crosshead die while being melt-extruded (impregnated) with an arbitrary amount of polypropylene resin in a molten state to aggregate the multiple glass fibers into one piece (pultrusion method), the fibers are hardly damaged, so it is preferred.

[0158] The length (extrusion direction) of the glass fiber-containing granules depends on the glass fiber used, but is generally 1 mm to 20 mm as described above. When using glass fiber-containing granules as the glass fiber, a longer glass fiber length (length of the glass fiber-containing granules) makes the manufacturing and processing of the granules easier; therefore, 3 mm to 18 mm is more preferred, 4 mm to 15 mm is more preferred, and 5 mm to 12 mm is particularly preferred. By making the length of the glass fiber, i.e., the length of the glass fiber-containing granules, within such a range, the rigidity, impact strength, and other physical properties, as well as the formability (flowability) of the acrylic resin composition of the present invention and the molded articles obtained therefrom, are all good. That is, if it is less than 1 mm, the rigidity, impact strength, and other physical properties of the acrylic resin composition of the present invention and the molded articles formed therefrom may decrease; on the other hand, if it exceeds 20 mm, the formability (flowability) and other properties may decrease.

[0159] Furthermore, the fiber diameter of the glass fiber is typically 3-25 μm, preferably 5-23 μm, more preferably 7-21 μm, and even more preferably 9-19 μm. By setting the fiber diameter of the glass fiber within this range, the dispersion in the polypropylene resin becomes good, thus enabling the flowability and mechanical properties of the resulting polypropylene resin composition to be maintained within a good range, while simultaneously exhibiting good flame retardancy.

[0160] Furthermore, in the glass fiber-containing granules, based on 100% by weight of the total granules, the glass fiber content is preferably 20% to 70% by weight. When glass fiber-containing granules with a glass fiber content in this range are used in the present invention, the rigidity, impact strength, and formability (flowability) of the acrylic resin composition of the present invention and the molded articles formed therefrom are all good. That is, when glass fiber-containing granules with a glass fiber content of less than 20% by weight are used in the present invention, the rigidity, impact strength, and other physical properties of the acrylic resin composition of the present invention and the molded articles formed therefrom may decrease. On the other hand, when glass fiber-containing granules with a glass fiber content of 70% by weight or more are used, the formability (flowability) and other properties may decrease.

[0161] (4) Additives (D)

[0162] In the propylene resin composition of the present invention, in addition to the polypropylene resin (A), flame retardant (B) and fiber (C), additives (D) that are any components used in the polypropylene resin may be appropriately blended as needed, without prejudice to the purpose of the present invention.

[0163] Examples of additives (D) include nucleating agents, molecular weight regulators, foaming agents, pigments, ultraviolet absorbers, antioxidants, antistatic agents, neutralizing agents, metal passivators, stabilizers, antibacterial agents, inorganic fillers, and rubbery components.

[0164] As a molecular weight reducing agent, various organic peroxides and substances known as decomposition (oxidation) promoters can be used, with organic peroxides being preferred. Specific examples of organic peroxides include those selected from benzoyl peroxide, tert-butyl perbenzoate, tert-butyl peracetate, tert-butyl peroxyisopropyl carbonate, 2,5-di-methyl-2,5-di-(benzoylperoxy)hexane, 2,5-di-methyl-2,5-di-(benzoylperoxy)hexyn-3, tert-butyl-di-peradipic acid ester, tert-butyl peroxy-3,5,5-trimethylhexanoate, methyl-ethyl ketone peroxide, cyclohexanone peroxide, di-tert-butyl peroxide, dicumyl peroxide, 2,5-di-methyl-2,5-di-(tert-butylperoxy)hexane, 2,5-di- One or more of the following groups: -methyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis-(tert-butylperoxyisopropyl)benzene, tert-butylcumyl peroxide, 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis-(tert-butylperoxy)cyclohexane, 2,2-bis-tert-butylperoxybutane, p-menthane hydroperoxide, di-isopropylbenzene hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, p-cymene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and 2,5-di-methyl-2,5-di-(hydroperoxy)hexane. It should be noted that this group is not limited to these.

[0165] There are no particular limitations on the types of foaming agents that can be used in this invention; known foaming agents used in plastics, rubber, etc., can be used. Furthermore, various foaming agents used in foaming molding can be used, such as physical foaming agents, decomposition foaming agents (chemical foaming agents), and microcapsules containing thermal expansion agents. Specific examples of physical foaming agents include: aliphatic hydrocarbons such as propane, butane, pentane, and hexane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; halogenated hydrocarbons such as difluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane, dichlorodifluoromethane, chloromethane, dichloromethane, dichlorotrifluoroethane, dichlorofluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafluoroethane, and perfluorocyclobutane; and inorganic gases such as water, carbon dioxide, and nitrogen. These compounds can be used alone or in combination.

[0166] Among these, aliphatic hydrocarbons such as propane, butane, and pentane, and carbon dioxide are preferred, considering their low cost and high solubility in polypropylene resins. In particular, when using carbon dioxide, if supercritical conditions of 7.4 MPa or higher and 31°C or higher are set, it achieves excellent diffusion and solubility in the propylene resin composition, and is therefore further preferred.

[0167] When using physical foaming agents, bubble regulators can be used as needed. Examples of bubble regulators include: inorganic decomposing foaming agents such as ammonium carbonate, baking soda (sodium bicarbonate), ammonium bicarbonate, and ammonium nitrite; azo compounds such as azodicarbonamide, azobisisobutyronitrile, and diazoaminobenzene; nitroso compounds such as N,N'-dinitrospentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosterephthalamide; organic decomposing foaming agents such as benzenesulfonyl hydrazine, p-toluenesulfonyl hydrazine, p,p'-oxobisbenzenesulfonamide, p-toluenesulfonamide, trihydrazine triazine, and barium azodicarbonate; inorganic powders such as talc and silica; acidic salts of polycarboxylic acids; and reaction mixtures of polycarbonates with sodium carbonate or sodium bicarbonate. These bubble regulators can be used alone or in combination.

[0168] When using a bubble regulator, the amount of bubble regulator mixed in is preferably set to 0.01 to 5 parts by weight of pure components relative to 100 parts by weight of the acrylic resin composition.

[0169] Specific examples of decomposable foaming agents (chemical foaming agents) include mixtures of sodium bicarbonate and organic acids such as citric acid, azodicarbonamide, barium azodicarbonate and other azo-based foaming agents, N,N'-dinitrospentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosterephthalamide and other nitroso-based foaming agents, p,p'-oxobisbenzenesulfonylhydrazine, p-toluenesulfonamide and other sulfonylhydrazine-based foaming agents, trihydrazine triazine, etc.

[0170] The amount of foaming agent mixed with 100 parts by weight of acrylic resin composition is preferably in the range of 0.05 to 6.0 parts by weight, more preferably 0.05 to 3.0 parts by weight, even more preferably 0.5 to 2.5 parts by weight, and particularly preferably 1.0 to 2.0 parts by weight.

[0171] In addition, any known organic or inorganic pigments can be used as pigments. Specifically, examples include organic pigments such as azo, anthraquinone, phthalocyanine, quinacridone, isoindolinone, dioxazine, violetone, quinophthalone, and perylene pigments, as well as inorganic pigments such as ultramarine, titanium dioxide, titanium yellow, iron oxide (iron oxide red), chromium oxide, zinc white, and carbon black.

[0172] As light stabilizers and ultraviolet absorbers, such as hindered amine compounds, benzotriazoles, benzophenones, and salicylates, they are effective in imparting and improving the weather resistance and durability of the acrylic resin compositions of the present invention and the molded articles thereof. For specific examples, hindered amine compounds include the condensation of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine; poly[[6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]; tetra(2,2,6,6-tetramethyl-4-piperidinyl)1,2,3,4-butanetetracarboxylate; tetra(1,2,2,6,6-pentamethyl-4-piperidinyl)1,2,3,4-butanetetracarboxylate; Examples of benzotriazole derivatives include bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and bis-2,2,6,6-tetramethyl-4-piperidinyl sebacate. Other examples of benzotriazole derivatives include 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole. Examples of benzophenone derivatives include 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. Examples of salicylate derivatives include 4-tert-butylphenyl salicylate and 2,4-di-tert-butylphenyl-3',5'-di-tert-butyl-4'-hydroxybenzoate. The combination of the above-mentioned light stabilizers and UV absorbers significantly improves weather resistance and durability, and is therefore preferred. Two or more of these can be used in combination.

[0173] As antioxidants, such as phenolic, phosphorus-based, and sulfur-based antioxidants are effective in imparting and improving the heat resistance, processing stability, and heat aging resistance of the polypropylene resin composition of the present invention and the molded articles thereof.

[0174] Antistatic agents, such as nonionic and ionic antistatic agents, are effective in imparting and improving the antistatic properties of the acrylic resin composition of the present invention and the molded articles thereof.

[0175] In particular, as antistatic agents, cationic, anionic, nonionic, amphoteric, plasma, and fatty acid partial esters such as glycerol fatty acid monoesters can be used.

[0176] Specifically, examples include alkyl trimethylammonium salts, dialkyl dimethylammonium salts, alkyl benzyl dimethylammonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methylammonium methyl sulfate, (3-lauramidopropyl)trimethylammonium methyl sulfate, stearamidopropyl dimethyl-2-hydroxyethylammonium nitrate, stearamidopropyl dimethyl-2-hydroxyethylammonium phosphate, cationic polymers, alkyl sulfonates, alkylbenzene sulfonates, and sodium alkyl diphenyl ether disulfonate. Alkyl nitrate salts, alkyl phosphate salts, alkyl phosphate amine salts, glyceryl monostearate, pentaerythritol fatty acid esters, sorbitan monopalmitate, sorbitan monostearate, diglyceride fatty acid esters, alkyl diethanolamine, alkyl diethanolamine fatty acid monoesters, alkyl diethanolamides, polyoxyethylene dodecyl ether, polyoxyethylene alkylphenyl ether, polyethylene glycol monolaurate, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyether block copolymers, cetyl betaine, hydroxyethyl imidazoline sulfate, etc. Two or more of these can be used in combination.

[0177] As nucleating agents, aromatic aluminum salt nucleating agents, aromatic sodium salt nucleating agents, aromatic metal phosphate nucleating agents, sorbitol nucleating agents, rosin nucleating agents, petroleum resins, talc, etc. can be used.

[0178] Examples of sorbitols, such as alkyl-substituted benzylidene sorbitol, include: 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di-(p-methylbenzylidene)sorbitol, 1,3-o-methylbenzylidene 2,4-p-methylbenzylidene sorbitol, 1,3,2,4-di-(p-ethylbenzylidene)sorbitol, and 1,3,2,4-di-(2',4'-dimethylbenzylidene)sorbitol. Examples of phosphorus-based sorbitols include sodium bis(4-tert-butylphenyl) phosphate, sodium 2,2'-ethide-bis(4,6-di-tert-butylphenyl) phosphate, and organophosphate complexes. Other examples include sodium benzoate, aluminum p-tert-butylbenzoate, sodium lignite, calcium lignite, alumina, kaolin, talc, rosin, and petroleum resins. Two or more of these can be used in combination.

[0179] Triazine, phosphine, epoxy, triazole, acylhydrazine, oxamide, and other metal passivating agents can be used.

[0180] Specifically, examples include N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, bis(2-phenoxypropionylhydrazine) isophthalate, disalicylic acid decanedicarboxylic acid hydrazine, bisbenzylidene oxalate, N,N'-bis{2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl}oxalamide, 3-(N-salicylic acid)amino-1,2,4-triazole, amides, melamine, and tris[2-tert-butyl-4-thio(2'-methyl-4'-hydroxy-5-tert-butyl)phenyl-5-methyl]phosphite. Two or more of these can be used in combination.

[0181] Various fatty acid metal salts can be used as neutralizing agents.

[0182] Specifically, examples include saturated or unsaturated fatty acids with molecular weights of approximately 26-300, such as oleic acid (unsaturated C18), stearic acid (C18), palmitic acid (C18), myristic acid (C14), lauric acid (C12), erucic acid (unsaturated C22), and behenic acid (C22), in combination with metal salts of lithium, sodium, calcium, magnesium, aluminum, zinc, etc. Two or more of these can be used in combination.

[0183] As an antibacterial agent, either organic or inorganic antibacterial agents can be used. Examples of organic antibacterial agents include chlorine-based, phenolic, imidazole-based, or thiazole-based compounds, quaternary ammonium compounds, etc. Examples of inorganic antibacterial agents include zeolite-based, apatite-based, silica-alumina-based, ceramic-based, zirconium phosphate-based, silica gel-based, hydroxyapatite-based, or calcium silicate-based antibacterial agents that retain metals such as silver and zinc.

[0184] Furthermore, specific examples of inorganic fillers include talc, barium sulfate, clay, silicon dioxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, glass fiber, and whiskers.

[0185] As a rubber-like component, substances known as elastomers or plastics can be used. Specifically, examples include ethylene-propylene rubber, ethylene-butene-1 rubber, ethylene-hexene rubber, ethylene-octene rubber, and styrene-butadiene rubber, etc., and various commercially available products can be obtained without inhibiting the effects of the present invention.

[0186] 2. Preparation method of acrylic resin composition

[0187] Examples of methods for preparing the propylene resin composition of the present invention include: a method of directly adding a predetermined amount of flame retardant (B), fiber (C), and additive (D) as needed to a powder or granules of polypropylene resin (A); a method of pre-preparing a masterbatch containing powder of polypropylene resin (A), flame retardant (B), fiber (C), and additive (D) as needed, and adding the masterbatch to granules of polypropylene resin; a method of first preparing a masterbatch of flame retardant (B) by adding flame retardant (B) and additive (D) as needed to powder or granules of polypropylene resin (A), and then preparing a masterbatch of fiber (C) by adding fiber (C) and additive (D) as needed to powder or granules of polypropylene resin (A), and then melt-blending the obtained masterbatch of flame retardant (B) and masterbatch of fiber (C), etc.

[0188] The polypropylene resin composition of the present invention can be obtained by any of the methods described above.

[0189] When using these methods, mixing can be performed using known methods such as drum mixers, super mixers, Henschel mixers, spiral mixers, and belt mixers. Melt mixing is not particularly limited as long as it is performed at a temperature above the melting point of the polypropylene resin (A), for example, using a melt extruder or a Banbury mixer.

[0190] The overall melt flow rate (MFR, 230°C, 2.16 kg load) of the acrylic resin composition of the present invention is typically 1 to 60 g / 10 min, preferably 2 to 50 g / 10 min, more preferably 5 to 40 g / 10 min, and particularly preferably 10 to 30 g / 10 min. By maintaining the overall MFR within this range, good formability can be maintained while obtaining good flame retardancy.

[0191] 3. Molding and Applications of Acrylic Resin Compositions

[0192] (1) Forming

[0193] Another aspect of the present invention is a molded article obtained from the acrylic resin composition of the present invention.

[0194] The acrylic resin composition of the present invention can be formed by injection molding (including gas injection molding) or injection compression molding (including pressure injection, hot flow molding, and gas injection compression molding). Among these methods, injection molding other than gas injection molding and injection compression molding (pressure injection) can more effectively achieve the effects of the present invention, and the molded article is preferably obtained by such molding methods.

[0195] In the molding of the acrylic resin composition of the present invention, various molding methods such as hollow molding, extrusion molding, compression molding, foaming molding, sheet molding, thermoforming, stamping molding, and powder molding can also be used as needed to obtain the desired molded body (e.g., an extruded molded body). Among these, molding methods other than foaming molding are preferred.

[0196] (2) Application

[0197] Applications of injection-molded articles obtained from the acrylic resin composition of the present invention include, for example, household appliance parts such as rice cookers, vacuum cleaners, washing machines, refrigerators, electric fans, and air conditioners; residential equipment parts such as dressing tables, exhaust fans, toilet seats, toilet lids, and housings of equipment used as accessories; general battery / battery pack peripheral components; and battery pack peripheral components for EV vehicles.

[0198] The invention is illustrated in more detail by way of examples, but the invention is not limited to these examples.

[0199] It should be noted that the evaluation methods and materials used in the embodiments are as follows.

[0200] 1. Evaluation Methods

[0201] 1) MFR of the resin section

[0202] The melt flow rate (MFR) of the resin section was measured according to JIS K7210 at a test temperature of 230°C and a load of 2.16 kg.

[0203] It should be noted that, in this embodiment, when multiple polypropylene resins are mixed and used as polypropylene resin (A), the melt flow rate (MFR) of the resin portion used is... A ) is calculated according to the logarithmic summation law according to the following formula (1).

[0204] log(MFR A = {(weight% of component (PP-A) × log(MFR of component (PP-A)) + (weight% of component (PP-B) × log(MFR of component (PP-B)) + (weight% of component (PP-C) × log(MFR of component (PP-C))} / 100 … Equation (1)

[0205] 2) Flame barrier test (fire resistance evaluation)

[0206] 2)-1. Evaluation of flame-stopping time

[0207] In an injection molding machine [Toshiba EC180, equipped with a long fiber screw], 170×170mm test pieces (thickness: 3.0mmt) were formed under the following conditions: barrel temperature: 200℃, mold temperature: 40℃, injection pressure: 60MPa, and injection speed: 60mm / sec. A flame-blocking test was then conducted. The details of the flame-blocking test are as follows.

[0208] A 125mm flame, similar to that used in UL94 5VA, is applied to the flat surface of the test specimen from below. The distance between the test specimen and the burner nozzle is set to 100mm. This flame contact is maintained for 15 minutes, and the time it takes for the flame to penetrate is recorded as the flame-stopping resistance time in the flame-stopping test. It should be noted that if flame penetration does not occur after 15 minutes of flame contact, the flame contact is terminated at that point. The evaluation of the flame-stopping resistance time is as follows.

[0209] ◎: No flame penetration occurred during the 15-minute flame contact period (recorded as >900).

[0210] 〇: Flame penetration occurs between 10 and 15 minutes.

[0211] △: Flame penetration occurs between 5 and 10 minutes.

[0212] ×: Flame penetration occurs in less than 5 minutes.

[0213] 2)-2. Evaluation of shape retention

[0214] For samples that did not experience flame penetration after 15 minutes in the aforementioned flame-blocking test, the shape retention of samples that were exposed to flame for 15 minutes in the aforementioned flame-blocking test was evaluated. The evaluation of shape retention is as follows.

[0215] ◎: No cracks or fragmentation were detected at the flame contact surface.

[0216] 〇: Cracks smaller than 1 cm were observed in the direction perpendicular to the flame contact surface (below the contact surface).

[0217] △: Cracks larger than 1 cm and smaller than 8 cm were observed in the direction perpendicular to the flame contact surface (below the flame contact surface).

[0218] ×: Cracks larger than 8 cm were observed in the direction perpendicular to the flame contact surface (below the flame contact surface).

[0219] - In the flame-blocking test, flame penetration occurred within 15 minutes, therefore it is not considered as a shape retention evaluation object.

[0220] 2)-3. Comprehensive evaluation of flame blocking performance

[0221] Based on the above evaluations of flame-stopping time and shape retention, a comprehensive evaluation is conducted as follows.

[0222] ◎: The case where both judgments result in ◎.

[0223] 〇: Cases where the flame-stopping time is marked with ◎, and the shape retention is marked with 〇 or △.

[0224] △: Case where the flame-resistance interruption time is determined to be 0.

[0225] ×: Cases where the flame-stopping time is judged as △ or ×, or the shape retention is judged as ×.

[0226] 3) Liquidity (spiral flow) evaluation

[0227] In an injection molding machine [Toshiba EC180, equipped with a long fiber screw], under the conditions of barrel temperature: 200°C, mold temperature: 40°C, injection pressure: 60MPa, and injection speed: 50mm / sec, injection molding was performed using a 20mm wide × 2.5mm thick spiral flow mold to produce 20mm wide × 2.5mm thick spiral flow test pieces. The length of the molded test piece was measured; the longer the piece, the higher the flowability. It should be noted that the evaluation of flowability is as follows.

[0228] ◎: 420mm or more

[0229] 〇: 370mm or more and less than 420mm

[0230] △: 320mm or more and less than 370mm

[0231] ×: Less than 320mm

[0232] 4) Mechanical properties (bending strength)

[0233] Measurements were performed at 23°C according to JIS K7203. The dimensions of the molded article are 90 × 10 × 4 mm, and the unit is MPa. Furthermore, the evaluation of mechanical properties is as follows.

[0234] ◎: Cases with a bending strength of 190MPa or higher

[0235] 〇: The bending strength is above 180MPa but less than 190MPa

[0236] △: Bending strength is above 170MPa but less than 180MPa

[0237] ×: Cases where bending strength is less than 170 MPa

[0238] 5) Overall Evaluation

[0239] Based on the comprehensive evaluation of flame blocking performance, fluidity evaluation, and determination of mechanical properties, the following comprehensive evaluation is conducted.

[0240] ◎: The case where there are no × and △ in all judgments, and only 〇 and ◎ are judged.

[0241] 〇: The case where there is no × in all judgments, all judgments are △ or higher, and at least one judgment is ○ or higher.

[0242] △: Cases where the result is △ in all judgments.

[0243] ×: The case where at least one of the decisions is × among all the decisions.

[0244] It should be noted that in the comparative examples, when any of the above evaluations is "×", the overall evaluation is also "×", so sometimes no other evaluation is performed.

[0245] 2. Materials

[0246] Polypropylene resin (A)

[0247] (A-1) Manufactured by Nippon Polypropylene Co., Ltd., NOVATEC PP series, MA1B (propylene homopolymer, MFR: 20g / 10 minutes)

[0248] (A-2) Manufactured by Nippon Polypropylene Co., Ltd., NOVATEC PP series, SA08A (propylene homopolymer, MFR: 75g / 10 minutes)

[0249] (A-3) Manufactured by Nippon Polypropylene Co., Ltd., NOVATEC PP series, MA3 (propylene homopolymer, MFR: 11g / 10min)

[0250] (A-4) Manufactured by Nippon Polypropylene Co., Ltd., NOVATEC PP series, MA04C (propylene homopolymer, MFR: 40g / 10 minutes)

[0251] (A-5) Manufactured by Nippon Polypropylene Co., Ltd., NOVATEC PP series, FY6H (propylene homopolymer, MFR: 2g / 10 minutes)

[0252] (A-6) Mix (A-3) above with an organic peroxide, adjust the MFR of (A-3), and use it as (A-6) (propylene homopolymer, MFR: 150g / 10min).

[0253] (A-7) Mix (A-3) above with an organic peroxide, adjust the MFR of (A-3), and use it as (A-7) (propylene homopolymer, MFR: 650g / 10min).

[0254] Organic flame retardants (B)

[0255] (B-1) FP2500S (phosphorus-based flame retardant containing polyphosphates) manufactured by ADEKA Co., Ltd.

[0256] Fiber (C)

[0257] (C-1) Glass fiber: manufactured by Nittobo Co., Ltd., RS2300, 2300TEX, fiber diameter 17μm

[0258] Other additives (D)

[0259] As other additives (D), antioxidants (D-1: Irganox 1010 manufactured by BASF), (D-2: Irgafos 168 manufactured by ADEKA Corporation), and maleic anhydride modified polypropylene (D-3: OREVAC CA100 manufactured by Arkema Corporation) are used.

[0260] 3. Preparation of various masterbatches (MB)

[0261] 1) Flame retardant masterbatch: Preparation of flame retardant MB-I and II

[0262] Polypropylene resin (A), phosphorus-based flame retardant (B), and other additives (D) were mixed in the proportions shown in Table 1 and mixed at room temperature for 3 minutes using a high-speed stirring mixer (Henschel mixer, trade name). Then, the mixture was melt-blended and extruded using a twin-screw extruder. After passing through a cold water tank, the granules were cut into wire rods using a wire rod cutter to obtain granules of the flame retardant masterbatch.

[0263] Table 1

[0264]

[0265] 2) Fiber Masterbatch: Production of Fibers MB-I and II

[0266] For fibers MB-I and MB-II, glass fibers (C) are guided from the fiber support in the form of fiber bundles to a resin impregnation tank containing polypropylene resin (A-6) or (A-7) heated to 270°C. After the polypropylene resin (A-6) or (A-7) impregnates the glass fiber bundles, they are pulled out through a circular nozzle in the impregnation tank, cooled, and then cut to obtain fiber MB-I granules (10 mm in length) and fiber MB-II granules (6 mm in length). It should be noted that the MFR of the polypropylene resin (A-6) or (A-7) in the impregnation tank, and the weight ratio of the polypropylene resin (A-6) or (A-7) to the glass fibers for each MB are shown in Table 2. At this time, relative to 100 parts by weight of the polypropylene resin (A-6) or (A-7) in the impregnation tank, 0.1 parts by weight of D-1, 0.05 parts by weight of D-2, and 0.4 parts by weight of D-3 are respectively mixed as additives.

[0267] Table 2

[0268]

[0269] 3. Preparation of test pieces

[0270] 1) Examples 1-16, Comparative Examples 1-8

[0271] The various masterbatches and polypropylene resins were mixed at the ratios listed in the dry mixing ratio column of Tables 3 and 4, and then molded using an injection molding machine. The mixtures were evaluated according to the evaluation method described above. The final composition of the propylene resin composition and the evaluation results are shown in Tables 3 and 4.

[0272] Table 3

[0273]

[0274] Table 4

[0275]

[0276] 4. Evaluation Results

[0277] The results shown in Tables 3 and 4 indicate that, relative to any amount of flame retardant, the melt flow rate (MFR) of the resin portion... A The lower the value of ), the higher the fire resistance and / or flame blocking performance. Specifically, it can be seen that in the order of Comparative Example 3 → Example 13 → Example 3, the melt flow rate (MFR) of the resin portion... A The value of the melt flow rate (MFR) gradually decreases, while the fire resistance and flame blocking properties gradually increase. Furthermore, comparing Example 14 with Comparative Example 2 reveals that the melt flow rate of the resin portion (MFR)... AWhile maintaining the same level, an increased ratio of flame retardant improves fire resistance and flame-blocking properties. Therefore, in this invention, controlling the amount of flame retardant and the melt flow rate (MFR) of the resin portion... A These two parameters are important for fire resistance and flame blocking properties.

[0278] On the other hand, relative to any amount of flame retardant, if the melt flow rate (MFR) of the resin portion is considered... A If the flow rate is reduced to a certain level, the fluidity decreases, becoming an obstacle in the manufacture of actual products. Therefore, in this invention, it is necessary to consider the balance between fire resistance, flame retardancy, and fluidity, and to optimize the melt flow rate (MFR) of the resin section based on the fiber content and the amount of flame retardant. A That is, in Comparative Example 1, the fire resistance and flame barrier properties were good, but the fluidity was low, suggesting that a higher melt flow rate (MFR) in the resin portion is needed for practical application. A ).

[0279] Furthermore, the present invention proposes a composition that not only exhibits excellent fire resistance, flame blocking properties, and flowability, but also excellent mechanical strength. For example, as in Comparative Example 8, the mechanical strength decreases when the concentration of fiber (C) is reduced. Therefore, in order to propose a composition with an excellent balance of fire resistance, flame blocking properties, flowability, and mechanical properties, it is necessary to have a fiber (C) concentration of 30% by weight or more.

[0280] As can be seen from these examples and comparative examples, the compositions specified in this application can achieve a balance of high fire resistance, flame blocking and flowability.

Claims

1. A acrylic resin composition, characterized in that, It contains a polypropylene resin (A) that satisfies requirement (A1), a flame retardant (B) that satisfies requirement (B1), and a fiber (C) that satisfies requirement (C1), and also satisfies conditions 1 and 2. Requirements (A1) Polypropylene resin (A) comprises at least one propylene polymer selected from the group consisting of propylene homopolymers, propylene random copolymers, and propylene block copolymers. Requirements (B1) Flame retardant (B) is an organic flame retardant. Requirements (C1) Fiber (C) is glass fiber, Condition 1 The acrylic resin composition contains 24-65% by weight of polypropylene resin (A), 5-26% by weight of flame retardant (B), and 30-50% by weight of fiber (C) (wherein, the total of polypropylene resin (A), flame retardant (B), and fiber (C) is 100% by weight). Condition 2 The melt flow rate (MFR, 230℃, 2.16kg load) of the polypropylene resin (A) and the content of the flame retardant (B) (wherein, the total of the polypropylene resin (A), flame retardant (B) and fiber (C) is set as 100% by weight) satisfy either (Condition 2-1) or (Condition 2-2) below. (Condition 2-1) The content of flame retardant (B) (in % by weight, where the total of polypropylene resin (A), flame retardant (B), and fiber (C) is set at 100% by weight) is 5% by weight or more and less than 18% by weight, and the melt flow rate (MFR, 230°C, 2.16 kg load) of polypropylene resin (A) is 75 g / 10 minutes or less. (Condition 2-2) The content of flame retardant (B) (in % by weight, wherein the total of polypropylene resin (A), flame retardant (B) and fiber (C) is set to 100% by weight) is 18% by weight or more and 26% by weight or less, and the melt flow rate (MFR, 230°C, 2.16kg load) of polypropylene resin (A) is 105g / 10min or less.

2. The acrylic resin composition according to claim 1, wherein, The polypropylene resin (A) further satisfies the following requirement (A2). Requirement (A2) The polypropylene resin (A) includes at least two types: polypropylene resin (Aa) and polypropylene resin (Ab), and the melt flow rate (MFR, 230°C, 2.16kg load) of the polypropylene resin (Aa) is in the range of 60~2000 / 10 minutes.

3. The acrylic resin composition according to claim 1, wherein, Fiber (C) further satisfies the following requirement (C2), Requirements (C2) As fiber (C), glass fiber with a fiber length of 1~20mm is used.

4. The acrylic resin composition according to claim 1, wherein, Flame retardant (B) is a phosphorus-based flame retardant.

5. The acrylic resin composition according to claim 4, wherein, Flame retardant (B) is a polyphosphate.

6. A molded article obtained from the acrylic resin composition according to any one of claims 1 to 5.

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