JPS61275344A - Light-diffusing vinylidene fluoride resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled resin compsn. which is freed from the problem of yellowing caused by prolonged ultraviolet light irradiation, by dispersing a vinylidene fluoride resin, a methacrylate ester resin and a light-diffusing agent in one another. CONSTITUTION:A resin compsn. is obtd. by dispersing a vinylidene fluoride resin, a methacrylate ester resin and a light-diffusing agent in one another. Examples of the vinylidene fluoride resins are vinylidene fluoride homopolymer and copolymers thereof with other copolymerizable monomer. Examples of the copolymerizable monomers are ethyl methacrylate, butyl methacrylate and alkyl acrylates. Examples of the light-diffusing agents are calcium carbonate, titanium carbonate, talc and silica. The mixing ratio of the vinylidene fluoride resin to the methacrylate resin is 98-30wt%/2-70wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a heptabenide-based resin composition with excellent light diffusivity, and more specifically to weather resistance, especially resistance to long-term ultraviolet irradiation. The present invention relates to a light-diffusing vinylidene fluoride resin composition with improved yellowing.

(Prior technology) Light-diffusing plastic sheets have been developed from a variety of materials, including acrylic resin sheets, and are used as sheet-like products including plates, and recently as thin films. It's starting to look like this. These light-diffusing plastic sheets are used for lighting, glazing, signboards, rear projection screens that project characters etc. from the rear like microfilm readers, and applications with similar functions. For the purpose of ensuring the brightness of print films such as landscapes and various movie advertisements at coffee shops, department stores, stations, etc.
For example, a milky white diffusion sheet is used to diffuse the light source and prevent glare.

The manufacturing method of these light-diffusing plastic sheets includes a method of applying a light-diffusing agent such as calcium carbonate, titanium oxide, barium sulfate, talc, or silica to the surface of a transparent plastic sheet; In addition to mixing and dispersing a light diffusing agent in a transparent plastic, blending polymers with different refractive indexes, and creating fine irregularities on the surface of a sheet, the main method is to mix and disperse a light diffusing agent in a transparent plastic. A method of mixing and dispersing is used.

By the way, as can be seen from the usage, even when these light-diffusing plastic sheets are used outdoors, they are destined to be strongly exposed to light, especially light in the ultraviolet region. Currently, various materials are used, including acrylic resin, but when exposed to UV rays for a long period of time, the sheet yellows, resulting in a decrease in brightness and a change in color tone. The reality is that there is a strong demand for improvement in weather resistance, especially yellowing.

(Problems to be Solved by the Invention) In view of these points, the present inventor selected a vinylidene fluoride resin with excellent weather resistance as the plastic base material, and also added a resin with high light transmittance. Therefore, in order to control the opacity (cloudiness) caused by crystallization of the vinylidene heptanide resin, and to improve the processability during sheet molding, methacrylic resin and a light diffusing agent are mixed. The present inventors have discovered that by dispersing the resin, a vinylidene fluoride resin composition with excellent light diffusivity and improved weather resistance, particularly yellowing caused by long-term ultraviolet irradiation, can be obtained, and the present invention has been completed.

(Another Means to Solve the Problems) That is, the present invention provides a light-diffusing vinylidene fluoride AU resin characterized by mixing and dispersing a vinylidene heptatide resin, a methacrylic acid ester resin, and a light diffusing agent. It is a type resin composition.

The pyridene fluoride resin used in the present invention refers to a homopolymer of vinylidene heptadide or a copolymer of C disdene fluoride and a copolymerizable monomer. Examples of copolymerizable monomers include vinyl fluoride, tetrafluoroethylene, and trifluorochloroethylene.

Next, the methacrylic acid ester resin refers to a homopolymer of methyl methacrylate as well as a copolymer of a monomer copolymerizable with methyl methacrylate.

Examples of copolymerizable monomers include ethyl methacrylate, zotyl methacrylate, and alkyl esters of acrylic acid.

The mixing ratio of vinylidene fluoride resin and methacrylic acid ester resin is 98 to 30% by weight/2 to 70% by weight.
Preferably it is 95-45% by weight, 15-55% by weight, more preferably 90-55% by weight/10-45% by weight.

The reason for this is that when the vinylidene heptatide resin exceeds 98% by weight, a certain amount of crystallization occurs even when the sheet obtained during molding is rapidly cooled, resulting in a decrease in light transmittance and poor sheet processability. Furthermore, if the vinylidene fluoride resin is less than 30% by weight, the light transmittance and sheet processability are excellent, but the desired improvement in weather resistance is not noticeable and the result is on the same level as that of acrylic resin sheets. I end up.

Next, as the light diffusing agent to be mixed and dispersed with the vinylidene fluoride resin and methacrylic acid ester resin, for example, calcium carbonate, titanium oxide, barium sulfate, talc, silica, aluminum hydroxide, glass beads, etc. may be used alone or 2. Can be used in combination of two or more species. The particle size of these light diffusing agents is not particularly limited, but those having an average particle size of generally used 0.1 to 100 microns, preferably several microns to several tens of microns, are suitable.

Furthermore, the amount of light diffusing agent added cannot be specified as it varies depending on the thickness of the molded product, but considering light diffusivity and transparency, it is necessary to It is preferable to use it in a range of 0.5 to 10 parts by weight. In addition, when mixing and dispersing the light diffusing agent into the vinylidene heptadide resin and the methacrylic acid ester resin, higher fatty acids, salts thereof, etc. can be used as dispersion aids. Further, ultraviolet absorbers can also be used within a range that does not affect the transparency or whiteness of the molded product or sheet.

Next, the raw materials to be used when manufacturing the composition may be prepared by premixing resin and light diffusing agent, etc. with a simple mixer such as a tumbler type mixer, or may be used as raw materials as is, or this blended material may be used as a raw material. It is also possible to use pellets obtained by melt-kneading them in advance using an extruder or the like as a raw material.

As the melt-kneading device, a single-screw or twin-screw extruder, a kneader, a Banbury mixer, or a high-speed rotary kneader such as a 'vcM kneader manufactured by Kobe Steel, Ltd. can also be used.

Next, extrusion molding is most suitable for producing the light-diffusing vinyl heptadide resin sheet of the present invention, and there are T-die method and inflation die method, both of which can be employed. Note that during sheet molding, especially when the vinylidene fluoride resin has high miscibility, it is preferable to rapidly cool the sheet material after it flows out from the die. In addition, other molding methods such as injection molding and blow blow molding can also be used to produce light-diffusing molded products.

The light-diffusing vinylidene fluoride resin sheets and molded products obtained in this way are used in a thickness range of 0.06 to 3.0 mm, and the sheets are heated when used for lighting equipment, signboards, etc. In some cases, it is molded.

Note that if the sheet is thin, it can also be used by laminating it with other transparent plastic sheets. It is also possible to color the sheet or emboss the surface of the sheet to an extent that does not affect the light diffusivity.

(Example) The present invention will be explained in detail below with reference to Examples.

From now on, vinylidene fluoride resin will be used as X'VD1F.
.

The methacrylic acid ester resin will be abbreviated as PMMA.

The fluorinated nylidene resin is manufactured by Pennwalt Co., Ltd. under the trade name Kynar 740 (hereinafter abbreviated as -740), while the methacrylate ester resin is manufactured by Mitsubishi Rayon Co., Ltd. under the trade name Acryvet MD (methyl methacrylate). Resin (hereinafter abbreviated as MD) and manufactured by the same company, product name Hypet HBI
(Methyl methacrylate resin containing acrylic rubber, hereinafter abbreviated as HBffi) was used.

Next, the light diffusing agents used were calcium carbonate-based products manufactured by Shiraishi Calcium Industries Co., Ltd. under the trade name Shibron A and Shiraishi Calcium Industries Co., Ltd. under the trade name Whiten 8B, and titanium oxide under the trade name R-820 manufactured by Gohara Sangyo Co., Ltd. , 8102 series [Fuji Dit
The product name Thyroid +244 manufactured by Son Kagaku Co., Ltd. was used.

The raw materials used to mold the light-diffusing sheet samples of each composition by injection molding or extrusion molding were I'VDI.
! ', PMMA, and a light diffusing agent were blended at a constant ratio, and then melted into pellets using a 30 tmφ counter-rotating twin-screw extruder for use.

Example 1 Raw material obtained by adding 1 part by weight of a calcium carbonate light diffusing agent (Siburon A) to 100 parts by weight of an 80:20 mixture of pvny (K-740) and PMMA (MD) and pelletizing it using a twin-screw extruder. Using a 5-ounce injection molding machine manufactured by Toshiba Machine Co., Ltd., a 2N thick plate sample was molded into 120 balls and 120 m long. As a result of evaluating the optical properties and weather resistance of this sheet sample at a mold temperature of 50°C, as shown in Table 1, it showed excellent light diffusivity and excellent color stability against ultraviolet rays even in long-term accelerated weather resistance tests. Indicated.

Example 2 PVDF (K-740) and PMMA (MD:
Titanium oxide light diffusing agent (R-820) is added to 100 parts by weight of a 60:40 mixture of HEIIf: 1:1 blend product).
Adding 0.5 parts by weight and 0.5 parts by weight of a calcium carbonate-based light diffusing agent (Whiten 8B'), the pelletized raw material was used in an extruder with a diameter of 40 m, a width of 500 m, and a slit of 0.5 parts.
Sheet samples were molded using 7 Dragon's coat hanger type die equipment. The thickness of this sheet sample was 0.22 m, and as a result of evaluating its optical properties and weather resistance, it showed excellent performance as shown in Table 1.

Example 6 PVDIF (K-740 and FMMA (MD)
Using the same equipment as in Example 1, injection-molded plate-like samples with a thickness of 1M and 1M were molded using the same equipment as in Example 1, using 100 parts by weight of the 50:50 mixture and the light diffusing agent shown in Table 1 blended into pellets. The optical properties and weather resistance evaluation results are shown in Table 1.

Example 4 PVDIF (K-74Q) and PMMA (HB
II! ) Extrusion sheet molding was performed using the same equipment as in Example 2 using a raw material obtained by blending 100 weight parts of Noah 0:301 compound with the light diffusing agent shown in Table 1 and making it into pellets.
A sample with a thickness of 0.5 m was obtained. The optical properties and weather resistance evaluation results are shown in Table 1.

Example 5 Using a raw material obtained by blending 100 parts by weight of a 0:40 mixture of pvny (K-740) and PMMA (MD) with the light powder shown in Table 1 and pelletizing it, an extruder 40 was used.
A sample was molded using a spider spiral type inflation die equipment with a diameter of 1gφ, 60w5φ, and a slit of 0.5m to obtain a film sample with a thickness of 0.10m. The optical properties and weather resistance evaluation results are shown in Table 1.

Example 6 PVDT (K-740) and PMMA (MD)
Using a pelletized raw material obtained by blending 100 parts by weight of the 80:20 mixture with the light diffusing agent shown in Table 1, a film sample was prepared using an extruder 65w1φ, a width of 1200mm, and a coat hanger type die equipment with a slit of 0.4m. was molded. Immediately after exiting the die, the film was crimped with a metal roll and an imroll. The thickness of this film sample is 0
．． As a result of evaluating its optical properties and weather resistance in 07y, it showed excellent performance as shown in Table 1.

Comparative Example 1 Using a pelletized raw material obtained by adding 1.0 parts by weight of a calcium carbonate light diffusing agent (Siburon A) to PMMA (MD), using the same equipment as in Example 1, the thickness of 120 nm, 120 mm, and 2 mm was used. An injection molded sample was obtained.

The optical properties and weather resistance evaluation results are shown in Table 2.

Comparative Examples 2 to 4 Optical properties and weather resistance were evaluated for three types of PMMA-based light-diffusing sheets, acrylic resin-based light-diffusing sheets, and cellulose-based light-diffusing sheets, which are commercially available or used in practical applications. The results are shown in Table 2.

Note that the properties of the sheets in Examples and Comparative Examples were measured based on the following method.

■Total light transmittance: Compliant with A8TM D-1003 ■Haze: 〃l ■Light diffusion: Distance between the fluorescent lamp and the sheet when the shape of the fluorescent tube becomes invisible (cm) ■Yellowness: J Engineering 5K-7103 Yellowness index: Yellowness after weathering promotion/initial yellowness ■Weathering promotion method: Sunshine Weatherme → -J Engineering 8A
-1415 (Effect of the invention) The present invention is a light-diffusing vinylidene fluoride-based resin composition in which a nylidene fluoride-based resin, a meccrylic acid ester-based resin, and a light diffusing agent are mixed and dispersed. Moreover, it has excellent color stability (resistance to yellowing) against long-term ultraviolet irradiation, so it can be used for lighting, glazing, signboards, rear projection screens, etc.

Patent Applicant Denki Kagaku Kogyo Co., Ltd. Procedural Amendment June 28, 1985 Director General of the Patent Office Manabu Shiga1, Indication of Case Patent Application No. 116512, 19852, Name of Invention Light Diffusing Vinylidene Fluoride System Resin composition 6, relationship with the case of the person making the amendment Patent applicant address: 1-4-1 Yurakucho, Chiyoda-ku, Tokyo Column 5 of the detailed description of the invention in the specification, Contents of amendment 1, Page 2 of the specification In the first line, ``Mo, rays'' should be corrected to ``Even when used indoors.''

2. "Mixability" on page 7, line 4 of the specification is changed to "mixture 3,"
[PVDF (K-740 and]) on page 10, line 4 of the specification is corrected to "' PVDF (K-740)."

Claims (1)

[Claims] A light-diffusing vinylidene fluoride resin composition prepared by mixing and dispersing a vinylidene fluoride resin, a methacrylic acid ester resin, and a light diffusing agent.