Cellulose ester composition and molded article

Abstract

To provide a cellulose ester composition that has good fluidity and gives a molding having resistance to water droplet marks.SOLUTION: A cellulose ester composition contains 100 pts.mass of (A) a cellulose ester, 19 to 45 pts.mass of (B) a citrate compound having a water solubility of 2 g / 100 ml or less, and 1 to 9 pts.mass of (C) an adipate compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to cellulose ester compositions and molded articles obtained therefrom. [Background technology]

[0002] Cellulose esters such as cellulose acetate generally have poor thermoplasticity and are therefore usually used in compositions containing a plasticizer. Patent Document 1 describes that 1 to 50 parts by mass of the adipic acid esters represented by the formulae (I) to (III) can be blended with 100 parts by mass of the cellulose ester. Patent Document 2 describes a cellulose ester composition containing 5 to 50 parts by mass of (B) an adipate ester compound and 1 to 50 parts by mass of (C) a phosphate ester having a cresyl group represented by general formula (I) relative to 100 parts by mass of (A) a cellulose ester, in which bleeding out of the plasticizer is suppressed. Patent Document 3 describes a cellulose ester composition containing, relative to 100 parts by mass of (A) cellulose ester, 5 to 50 parts by mass of (B) a phosphoric acid ester having a naphthyl group represented by general formula (I), and 5 to 40 parts by mass of (D) an ester-based plasticizer other than (B), and describes that the composition has high thermoplasticity and can give a resin molded product with good mechanical strength. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5798640 [Patent Document 2] Patent No. 6038639 [Patent Document 3] Patent No. 6170654 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a cellulose ester composition having good fluidity and a molded article obtained therefrom that can suppress the occurrence of water droplet marks. [Means for solving the problem]

[0005] The present disclosure provides a cellulose ester composition containing (A) 100 parts by mass of a cellulose ester, (B) 19 to 45 parts by mass of a citrate ester compound having a solubility in water of 2 g / 100 ml or less, and (C) 1 to 9 parts by mass of an adipate ester compound. [Effects of the Invention]

[0006] The cellulose ester composition of the present disclosure has good fluidity, and molded articles obtained from the composition have a good flexural modulus and are prevented from generating water stains even when water droplets are attached thereto. DETAILED DESCRIPTION OF THE INVENTION

[0007] (composition) <Component (A)> The cellulose ester of the component (A) is known (for example, as described in JP-A-2005-194302), and examples thereof include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate. Other examples include polycaprolactone-grafted cellulose acetate, acetyl methyl cellulose, acetyl ethyl cellulose, acetyl propyl cellulose, acetyl hydroxyethyl cellulose, and acetyl hydroxypropyl cellulose. Of these, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate are preferred.

[0008] The cellulose ester of component (A) preferably has an average degree of substitution of 2.7 or less. The cellulose ester of the component (A) preferably has a viscosity average degree of polymerization of 100 to 1,000, more preferably 100 to 500.

[0009] <(B) component> The citrate ester compound (B), whose solubility in water (25°C) is 2 g / 100 ml or less, is a component that, when used in combination with component (C), increases the fluidity of the composition and, in particular, acts to suppress the occurrence of water stains. The solubility in water of component (B) is preferably 1.5 g / 100 ml or less. An example of component (B) is acetyltriethyl citrate. Component (B) can be a commercially available product, for example, "Citroflex A-2" (solubility in water: 0.72 g / 100 ml [25°C]) (Morimura Shoji Co., Ltd.).

[0010] <(C) component> The adipic acid ester compound of component (C) is a component that, when used in combination with component (B), increases the fluidity of the composition and, in particular, acts to increase the flexural modulus and impact strength. The adipic acid ester compound of component (C) contains at least one compound selected from the adipic acid esters shown in the following formulae (I), (II), and (III) described in Japanese Patent No. 5798640. Component (C) may be any one selected from the adipic acid esters represented by formulas (I), (II), and (III), or may be a mixture of any two of (I) and (II), (I) and (III), or (II) and (III), or may be a mixture of (I) to (III).

[0011] [ka]

[0012] The contents of the (A), (B), and (C) components in the composition of the present disclosure are, relative to 100 parts by mass of the (A) component, 19 to 45 parts by mass of the (B) component, preferably 20 to 40 parts by mass, and 1 to 9 parts by mass of the (C) component, preferably 1.5 to 9 parts by mass.

[0013] The total content of components (B) and (C) in the composition of the present disclosure is preferably 20 to 45 parts by mass, and more preferably 25 to 40 parts by mass, per 100 parts by mass of component (A).

[0014] In order to suppress the occurrence of water stains, the content of the (B) component and the (C) component is preferably 79 to 95 mass%, more preferably 79 to 93 mass%, of 100 mass% of the total of the (B) component and the (C) component, and the content of the (C) component is preferably 21 to 5 mass%, more preferably 21 to 7 mass%.

[0015] The composition of the present disclosure may contain a known thermoplastic resin depending on the application. Examples of known thermoplastic resins include styrene-based resins such as ABS resin and AS resin, polycarbonate-based resins, polyolefin-based resins such as polyethylene and polypropylene, polyamide-based resins such as polyamide 6, polyamide 66, polyamide 610 and polyamide 612, acrylic-based resins, methacrylic-based resins, polyester-based resins, polyacetal-based resins, and polyphenylene sulfide-based resins. The content of the known thermoplastic resin is preferably 40% by mass or less, and more preferably 20% by mass or less, of the total amount including the cellulose ester of the component (A).

[0016] The compositions of the present disclosure may further contain a filler. The filler includes fibrous fillers and non-fibrous fillers (such as powdery or plate-like fillers), and examples thereof include those described in paragraphs 0025 to 0032 of JP-A No. 2005-194302. The content of the filler is preferably 5 to 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the cellulose ester of the component (A).

[0017] The composition of the present disclosure may contain a stabilizer such as an epoxy compound described in paragraphs 0035 to 0042 of JP-A No. 2005-194302, or an organic acid, thioether, or phosphite compound described in paragraphs 0043 to 0052.

[0018] The composition of the present disclosure may contain, depending on the application, conventional additives such as other stabilizers (e.g., antioxidants, ultraviolet absorbers, heat stabilizers, light stabilizers, etc.), colorants (dyes, pigments, etc.), antistatic agents, flame retardants, flame retardant aids, lubricants, antiblocking agents, dispersants, anti-dripping agents, antibacterial agents, etc.

[0019] The composition of the present disclosure preferably has an MI (g / 10 min) of 20 g / 10 min or more, and more preferably 20 to 70 g / 10 min.

[0020] The composition of the present disclosure may be prepared, for example, by dry or wet mixing the components using a mixer such as a tumbler mixer, a Henschel mixer, a ribbon mixer, or a kneader. Furthermore, a method of premixing in the mixer and then kneading the mixture in an extruder such as a single-screw or twin-screw extruder to prepare pellets, or a method of melt-kneading the mixture in a kneader such as a heated roll or a Banbury mixer to prepare pellets can also be applied.

[0021] (molded product) The compositions of the present disclosure can be molded into various molded articles by injection molding, extrusion molding, multi-layer extrusion molding, press molding, vacuum forming, profile molding, foam molding, injection pressing, press molding, blow molding, gas injection molding, and the like. The molded article of the present disclosure preferably has a flexural modulus (MPa) (ISO178) of 1800 MPa or more, more preferably 2000 MPa or more.

[0022] The composition of the present disclosure can be used to produce plain or patterned molded articles such as frames for sunglasses, eyeglasses, etc., tipping films for various shoelaces (used by heat-shrinking the film around the tip of the shoelace), goggles; cosmetic containers; oral care products such as toothbrush and interdental brush handles; makeup products such as cheek brush, eyebrow brush, and lip brush handles; hair care products such as hair accessories, hair dryers, hair irons, hairbrushes, and combs; writing instruments such as ink pen barrels; personal care products such as razor handles; toys; and household appliances and tools. In particular, eyeglass frames made using the composition of the present disclosure are excellent in processability, feel, color, and impact resistance. The above molded products can be produced using injection molding or the like, and molded products such as frames for sunglasses and spectacles can be produced by punching a single sheet or a laminate of multiple sheets. The sheet for manufacturing eyeglass frames can be manufactured by extruding the sheet from a T-die of an extruder, cutting the sheet, and repeatedly press-molding the sheet.

[0023] Each feature disclosed herein may be combined with any other feature disclosed herein. The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of the disclosure of the present invention. The present disclosure is not limited by the embodiments, but is limited only by the claims. [Example]

[0024] The cellulose ester (A), the citrate ester compound (B), and the adipate ester compound (C) shown in Table 1 were mixed using a Henschel mixer to a temperature of 70°C or higher due to frictional heat within the mixer. The mixture was then fed into a twin-screw extruder (cylinder temperature: 200°C, die temperature: 210°C) and extruded to form pellets. The obtained pellets were fed into an injection molding machine and injection-molded into test pieces under the conditions of a cylinder temperature of 220°C, a mold temperature of 50°C, and a molding cycle of 60 seconds (injection time 20 seconds, cooling time 40 seconds). These test pieces were used for the evaluation tests shown in Table 1.

[0025] <Ingredients used> Component (A) Cellulose ester: trade name "L50", degree of substitution 2.5, viscosity average degree of polymerization 180, manufactured by Daicel Corporation (B) Component Citrate ester compounds (including acetyltriethyl citrate): Trade name "Citroflex A-2" (solubility in water: 0.72 g / 100 ml [25°C]), Morimura & Co., Ltd. (C) Component Adipic acid ester compound (a mixture of the above formulas (I) to (III)): trade name "DF101", manufactured by Daihachi Chemical Industry Co., Ltd.

[0026] (Flexural modulus: MPa) Measurements were made in accordance with ISO178.

[0027] (Charpy impact strength: kJ / m 2 ) The notched Charpy impact strength was measured in accordance with ISO179 / 1eA.

[0028] (MI: g / 10 min) Measurements were taken at a temperature of 220°C and a load of 10 kg.

[0029] (Water drop marks) In a laboratory environment of 23°C and 50RH, two drops (0.1 to 0.4 ml) of pure water were placed on a 50 mm x 90 mm x 3 mm transparent plate using a whole pipette, and the water droplet marks remaining on the color plate were visually evaluated after 5 hours. ○: No water droplets were visible to the naked eye. △: By changing the angle of sunlight hitting the transparent plate, faint traces of water droplets could be seen. ×: Water droplets were clearly visible to the naked eye.

[0030] [Table 1]

[0031] As is clear from Table 1, in Examples 1 to 11, the components (B) and (C) were used in combination, and therefore well-balanced results were obtained in the four measurement items. Comparative Example 2 does not contain component (B), and Comparative Example 3 contains components (B) and (C) but contains a small amount of component (B). 3 is However, the occurrence of water droplet marks could not be suppressed. In particular, a comparison between Example 3 ((B) × 100 / [(B) + (C)]) = 79.7% by mass and Comparative Example 3 ((B) × 100 / [(B) + (C)]) = 78.3% by mass confirmed that the effect of suppressing water stains can be enhanced by adjusting the content of component (B) in the total amount of components (B) and (C) within a specified range. In Comparative Example 1, which did not contain component (C), the occurrence of water droplets was suppressed, but the fluidity and impact strength were poor. In Comparative Example 4, which did not contain component (C), the occurrence of water droplet marks was suppressed, but the flexural modulus and impact strength were poor. [Industrial Applicability]

[0032] The cellulose ester composition of the present disclosure can be used as a raw material for manufacturing frames for sunglasses, eyeglasses, and the like.

Claims

1. (A) 100 parts by mass of cellulose ester, (B) 19 to 45 parts by mass of a citrate ester compound having a solubility in water of 2 g / 100 ml or less; (C) A cellulose ester composition containing 1 to 9 parts by mass of an adipate ester compound.

2. 2. The cellulose ester composition according to claim 1, wherein the citrate ester compound of component (B) is acetyltriethyl citrate.

3. A cellulose ester composition according to claim 1 or 2, wherein the adipic acid ester compound of component (C) contains at least one selected from the adipic acid esters represented by the following formulas (I), (II), and (III): 【Chemical 1】

4. 4. The cellulose ester composition according to claim 1, wherein the total content of the components (B) and (C) is 20 to 45 parts by mass per 100 parts by mass of the component (A).

5. 4. The cellulose ester composition according to claim 1, wherein the content of the component (B) is 79 to 95 mass% and the content of the component (C) is 5 to 21 mass%, based on a total of 100 mass% of the components (B) and (C).

6. 6. The cellulose ester composition according to claim 1, wherein the cellulose ester of component (A) is selected from the group consisting of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

7. A molded article comprising the cellulose ester composition according to any one of claims 1 to 6.

8. The molded article according to claim 7, which is an eyeglass frame.

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