JPS5941343A - Polypropylene resin composition for container of magnetic recording material - Google Patents

Abstract

PURPOSE:To prepare the titled resin composition resistant to discoloration even sealing together with a magnetic recording material for a long period, by adding an organic phosphonite compound or organic phosphite compound as an antioxidant to the base resin. CONSTITUTION:The objective resin is prepared by adding (A) 0.01-0.5wt% preferably 0.03-0.3wt% of an antioxidant comprising an organic phosphonite such as tetrakis(2,4-di-t-butylphenyl) 4,4'-biphenylene-diphosphonite and/or an organic phosphite compound such as tris-(mono- or di-norylphenyl)phosphite to (B) a polypropylene resin which is a propylene homopolymer or a copolymer of propylene and other alpha-olefin and composed mainly of isotactic structure. The resin is suitable for the munufacture of a white or light-colored or non-colored molded article.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyglobylene resin composition for a magnetic recording medium housing member, and more particularly to a polypropylene composition that does not easily discolor even when sealed together with a magnetic recording medium for a long period of time.

Polypropylene resin has a crushing property of 7' (properties such as heat resistance, chemical resistance, rigidity, strength, hinge properties, embossing/
) has been used in magnetic tape cassettes, etc. in recent years due to its properties, but it may change color if it is colored with pigments, etc. in white, yellow, green, green, or similar colors. Color's match is outside 115i! Because of this, the product value is significantly reduced and it is difficult to put it into practical use.
c.

Polypropylene resins are inherently susceptible to oxidative deterioration and are used with the addition of some kind of antioxidant. However, polypropylene resin containing commonly used antioxidants does not cause discoloration even when used for general purpose coloring, but when used for applications such as cassette halves and cases for magnetic tapes, the color changes to yellow or pink. Tends to discolor. This phenomenon is presumed to be due to the effects of the composition used in the magnetic tape, antioxidants, etc.

A magnetic tape having a magnetic coating layer is made by coating magnetic particles on the surface of a paste such as a polyester film using a binder, and the magnetic material is IF e20s.
rFe304, Co-containing 1-Fe2O3.

Co-containing Fe3O4+ 'CrO2, Fe alloy powder, etc. are used. In addition, as a binder, vinyl chloride/vinyl acetate copolymer, nitrile rubber, polyurethane resin, nitrocellulose qui, polyvinyl butyl resin, epoxy resin, vinyl chloride/vinyl alcohol copolymer, vinylidene chloride/acrylonitrile copolymer, etc. is used,
As a hardening agent, poly-r-socyanate, etc., as a dispersant, lecithin, phosphoric acid ester, oligoester acrylate, sorbitan fatty acid ester, N-alkyl trimethylene diamine and its salt, carboxymethyl cellulose sodium salt, imbutene maleic anhydride. Toluene, methyl ethyl ketone, xylene, cyclohexane, etc. are used as solvents for copolymers, higher fatty acids and their conductors, etc.

It is presumed that a combination of these various substances causes discoloration of the polypropylene resin, but the cause is not clear. The inventors made contact with and/or crossed the magnetic tape.]
As a result of studying compositions that do not cause discoloration even when exposed to a certain place, the present invention was achieved.

The object of the present invention is to provide a polypropylene resin composition that does not change color even when sealed together with a magnetic recording material for a long period of time, and that can be quickly extracted from an organic phosphonate compound and an organic phosphite compound. If the oxidation vJ'r is more than 0.
01 Nai L 0.5 Contains 1% MM
r! j *.

The composition of the present invention can be used in a sealed p! Does it change color? [4I is indistinguishable and can be suitably used for the following purposes. For devices that use magnetic tape, there are so-called cassette halves or half cases for V i'R, recording, and small computers, flat contact cases that house cassette halves, and 'U' for reel-to-reel devices.
! It is possible to use a so-called file containing a floppy disk as a device that uses magnetic disks.

The polypropylene resin used in the present invention is a copolymer obtained by copolymerizing a polypropylene homopolymer mainly having an intact structure and an α-olefin other than propylene.

MFR (230°C12, 1fi kg load 1F, l'/
10 minutes]) is not particularly limited, but in the case of injection nV, mold use 1
4-100, 1-10 for sheet molding. Hollow formation! (!(
The quotient is O, B ~ 1.0.

Examples of organic phosphonite compounds and mechanical phosphite compounds include: tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite, bis(2,4-di-tert-butylphenyl) ) pentaerythritol-di-phosphite, tris-(nogynolylphenyl)phosphite)
・, distearylbentaerythritol-di-phosphite, thrineuryl-triteophosphite, 4,4'-bunalidene-bis(3-methyl-6-tert-butyl-phenyl-di-tridecyl-7-osphite and bis(hala- octyl)phenyl-bis[2-tert-butyl-5-methyl~α-(8-tert-butyl-6-methyl-4-hydroxyphenyl))? , 6-
The addition of 0.01f to polyglopylene-based resin compositions can be mentioned. Ishi 0.51fHW
L%, especially 0.03 to 0, aix disease% is preferable.When the U addition line is 0 and 1% by weight or less, the discoloration prevention effect is small, and when it is more than 0.5s=weight%, the discoloration prevention effect is low. Crude gold will be generated during the period when the amount has reached a plateau and l repread etc.

Effect L4 in the present invention! : Can be used in combination with antioxidants such as phenolic antioxidants and thio group-containing compound antioxidants as long as they do not lose their properties, and can be used with antistatic agents, ultraviolet absorbers, nucleating agents, slip agents, etc. Can be used in combination. Furthermore, even if a coloring agent such as a pigment is blended, a remarkable effect is exhibited, especially when a white coloring agent whose discoloration is easily noticeable is blended.

The organic phosphionite compound used in the present invention, in the case of Aizuki, is said to be an antioxidant D-2 agent! It is preferable that the amount is 4 mm or d or more, and when triblending, it can be used in combination with higher fatty acid calcium or zinc 2-ethylhexoinate to produce effects such as preventing cooking.

The compositions of the invention are suitable for producing white, light-colored or uncolored manufactured products. Pigments that can be added to the composition of the present invention include titanium white as a white thread pigment, copper phthalocyanine blue as a night color pigment, and #
As color pigments, mention may be made of cobalt violet and mixtures thereof.

The li product of the present invention is a tilted cylindrical mixer, a type mixer,
It can be mixed using a mixer such as a ribbon mixer or a turbine mixer, and it can also be pelletized.

The composition of the present invention can be formed by injection molding, sheet molding by extrusion method,
Sea 1 by calender method [can be applied to the force 11 method generally used for polyglobuly resins such as molding, press molding, hollow molding, etc.

The present invention will be illustrated below by way of examples.

Examples 1-15. Comparative Examples 1 to 4 (white sheet) The following components were used in the composition.

Polypropylene block copolymer powder (ethylene oil-containing 1%, M, F, R, 8,5 (y/10 min)) Organic phosphonite compound, organic 7-phosphite compound (1) Tetrakis (2,4-jeta-jarylphin) Terphenyl) 4.4'-biphenylenedi7osphonite (2) Bis(2,4-di-tert-butylphenyl)pentaerythritol-di-phosphite ■Tris(nogynolylphenyl)7osphite (4) Disteary Rubenta erythrite ~ rouzi phosphite ■ Trilauryl thiophosphite ■ 4,4'-
Bunaridene bis(8-methyl-6-tert-butyl-phenyl-di-tridecylphosphite) His(hala-octyl)phenyl-bis[2-tert-butyl-5-methyl-α-(3-tert-butyl- 6-methyl-4-hydroxyphenyl)) 1.6
-hexanethiol-diphosphite-laurin-based zinc phenolic antioxidant 7 As a 2.6-theter diarybutyrinochlear cresol (1,8.5-) rimether-2.4.6-trifle, (
8,5-di-tert-butyl-4-ha.f-drooxybenzoyl)benzene [Co., Ltd.] Tetrakis [methylene-
8-(3',5'-di-tert-buna-4'-hydroxyphenyl)propyl:4-;i-to]methane σpn-octadecyl-β-(4'-hydroxy-
8', 5'-di-tajaribnalphenyl) propione-1, 0 as a thio group-containing compound-based antioxidant, di-lauryl-β, β'-thiodiprobio as a lubricant and calcium sedearate 0. .1 Car 5f%
, 0.3% glycerin monostearate as a 4if'dL inhibitor, Titanium White 2N-1 as a pigment
4% (the numbers in the table are 1llsυ of each antioxidant)
The ratio of 11 to 1 is expressed as a crude percentage (4, which is 7).

The components of the composition were mixed for 5 minutes using a Henschel mixer and pelletized using a 40111JIφ single screw extruder set at 280°C. The pellets were passed through a 65mtsφ screw extruder (240'C).
It was extruded into a sheet using
Cool and solidify between the metal rolls of the book with i [il L
, a sheet with a thickness of 7 km was obtained.

The sheet was cut into the size of a video cassette and placed in contact with both sides of a video cassette, wrapped in aluminum foil and sealed with duct tape pasted at the joints of the aluminum foil. The sealed video cassette was placed in a heated oven kept at 60° C., and the sheet was examined for discoloration. The results are shown in Table 1.

As shown in Table 1, in the comparative example in which a phenolic antioxidant was used alone, it was observed that the color changed in 50 hours in an atmosphere of 60°C, and the color changed significantly in 100 hours, but the present invention Example 1 in which the antioxidant indicated by was added alone
-9, no discoloration was observed after 100 hours, but no discoloration was observed after 200 hours. Result 2 was obtained, and the discoloration performance was good even when the amount added was changed.

By using the antioxidant shown in the present invention in combination with the phenolic antioxidant, which has poor discoloration performance when added alone, the 1lfl discoloration performance could be significantly improved. Good results were obtained when a thio group-containing compound antioxidant was used in combination with the antioxidant shown in the present invention.

Examples 16-24. Comparative Examples 5 to 11 (uncolored, light-colored sheets) Tests were conducted according to Examples 1 to 15 and Comparative Examples 1 to 4, except that no pigment was included or a plurality of light-colored pigments were used. The state of discoloration of the sheet was examined. The pigments used were Copper Phthalocyanine Blue as a blue pigment, Kono Violet as a purple pigment, and Titanium White as a pigment used in combination. They have the same meaning, and the numbers in the pigment section indicate the amount added (expressed in %).

[Procedural Amendment Showa] ] Z month, 1958, Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. 41 Displays 1988 Patent Application No. 188086 2, Issued Title Polypropylene Resin for Magnetic Recording Body Housing Member Relationship with the case for amending Composition 3 Special K “Applicant No. 82, Nakanoshima 3-chome, Kita-ku, Osaka-shi, Osaka Prefecture (530)
(207) Chisso Corporation representative Sadao Nogi 4, agent Shinjuku 2-8 Shinjuku Shinjuku-ku, Tokyo No. 1 (160) 5, amendment order daily (Jiko Sodomi) 6. Inventions that increase due to amendment No number 7, "Detailed description of the invention" column of the specification subject to amendment.

8. Contents of amendment (1) Changed "Light color new color" on page 8, line 10 of the specification to "
Correct to "light color color".

(2) In the 3rd page of SuJ Station, lines 17 and 18, ``to do something yellow'' is corrected to ``to do something yellow, sometimes.''

(3) Insert "used in half-case" before "composition" on page 3, line 19 of the specification.

(4) Correct the following sentences from the 1st line on page 10 to the 15th line on page 11 of the specification.

Phonite (Swiss Zand AGXR Zand Starp P-EPQ) ■Bis(2,4-di-tert-butylphenyl)pentaerythritol-cyphosphite (Ultra Nox 6 manufactured by Borgner Chemicals Inc., USA)
26) Tovsu-(7-nodynolylphenyl)phosphite (Mark 829 manufactured by Adeka Argus Chemical)
) Distearylpentaerythritol-di-7 osphite (Weston 618, manufactured by Borg Warner Chemicals Inc., USA) ■ Trilauryl-root lithiophosphite (TLTI, manufactured by Ajitahe Kagaku Kogyo Co., Ltd.))
■4,4'-butylidene-bis(3-methyl-6-tertiary-phenyl-sheet-trisorcyl) phosphite (MarkP, manufactured by Adeka Arcus Chemical Co., Ltd.) ■Bis(hala-octyl)phenyl-bis[2- Tert-butyl-5-methyl-α-(3-tert-butyl-6-methyl-4-hydroxyphenyl)) 1.6
- Zinc hexanethiol diphosphite laurate (IVlark NHP-H manufactured by Adeka Argus Chemical) ■2.6-di-tert-butyl-para-cresol (Yoshitomi Pharmaceutical (L back of mouth BH'1) as a phenolic antioxidant ■1,8.5-)dimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzoyl)benzene (Switzerland Nabakagi-AG Rus Irganox 1880) [Phase] Tetrakis (methylene-8-(8',5'-di-
tert-bunaru-41-hydroxyphenyl)propione-1-)methane (Musashino Geigy (1'El Irgana, x 1010) n-octatecy-β-(4'-hydroxy-8', 5'-di-
Tertiary-butylphenyl) propionate (Muzashino Geigi@) g Irganox l (176
) As a thio group-containing compound-based antioxidant ■Dilauryl β,β'-theodipionate (Yoshitomi DLTP manufactured by Yoshitomi #Ka) As a lubricant Calcium stearate 0. I Ni%, glycerin monostearate as antistatic agent 0.8 weight-1d 77/,
Titanium White (Titon A-150, manufactured by Sakai Chemical Industry Co., Ltd.) 2 weight as a pigment (5) Insert the following cross-section under the 12th line on page 12 of the specification.

Separately, wrap each sheet in its entirety (without the video cassette metal wrapper) in five layers of aluminum foil and seal it by pasting Camchive on the seam of the aluminum foil.
When the sheet was placed in a heating oven kept at 0°C for 200 hours, no color was observed on the sheet. , J (6) Specification ￥1 Insert the following item to the right of [200Hr J in the rightmost package j (discoloration test) of Table 1 on page 13.

that's all

Claims (3)

[Claims] (1) A magnetic recording medium containing 0.01 to 0.5'4q% of one or more antioxidants selected from organic phosphionite compounds and organic phosphite compounds. Polypropylene resin composition for parts. (2) Claim 1, 'Jf', characterized in that it contains a white or light colored pigment or does not contain a pigment.
2. A polypropylene resin composition using a magnetic recording medium accommodating portion according to item 1. (3) The antioxidant is tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite, bis(2,4-di-tert-butylphenyl)pentaerythritol-ziphos tris-(7-nodynolylphenyl)phosphite, distearyl-pentaerythritol-di-7-osphite, trilauryl-trithiophosphite, 4,4'-butylidene-bis(8-methyl-6-turnyaly-bunaru) phenyl-di-tridecylphosphite and bis(hala-octyl)phenyl-bis[2-tert-butyl-5-methyl-α-(3-tert-butyl-6-methyl-4-hydroxyphenyl)); 6-
A polypropylene resin for a magnetic recording medium accommodating portion according to claim 1 or 2, characterized in that the polypropylene resin is 1 ar or 2 or more selected from hexanethioludi-7 osphite fatty acid monocarboxylic acids. Composition.