JPS60256918A - Lubricating agent for magnetic recording material - Google Patents

Abstract

PURPOSE:To obtain a recording material which is provided with excellent lubricity and has improved durability by incorporating >=1 kinds of specific organosilane compds. as a lubricating agent for the magnetic recording material into a magnetic layer. CONSTITUTION:A magnetic paint contg. 1 or >=2 kinds of the organosilane compds. expressed by formulas I, II (R<1> is an alkyl or alkenyl of 8-22C, R<2> is an alkyl of 1-3C, X is the residual group after removing an OH group from ditetrahydric alcohols, l is 0 or 1-5, m is 2-4, n is 2 or 3, p is 1-3) at 0.1- 10wt% by the weight of magnetic powder is prepd. Such paint is coated on a substrate consisting of a polyester film, etc. to form the magnetic layer. The recording material for a magnetic tape, disk, etc. which has excellent lubricity, has the lubricity stable with the lapse of time and excellent running property and durability is thus obtd.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a lubricant applied to magnetic recording materials in the form of tapes, disks, etc. , relates to a lubricant capable of imparting lubricity with excellent durability to the magnetic recording material.

In recent years, magnetic recording materials (hereinafter simply referred to as "materials") have developed rapidly, mainly for use in audio, video, and computers, and the generalization and diversification of these materials has led to new developments in these materials. On the other hand, many more advanced demands are being generated, such as improvements in recording density, durability, and reliability. Among these demands, many proposals have been made to improve recording density, such as improving magnetic powder, improving magnetic coatings, and perpendicular magnetization. It is essential to make the shift flat. However, this flattening of the material surface increases the frictional force of contact between the material surface and other objects such as magnetic nodes, which makes it difficult for the material to run smoothly and causes wear and tear on the material surface. Therefore, there is a strong demand for a lubricant that can be applied to the material and provide the material with lubricity having excellent durability. The present invention provides a lubricant that meets these demands.

<Prior Art> Conventionally, various types of additives have been added to magnetic paints and applied to the material in order to provide the material with lubricity that improves the runnability of the material and reduces wear and damage on the material surface. Examples of proposed compounds include long-chain fatty acids such as palmitic acid, stearic acid, and oleic acid, fatty acid esters such as n-butyl stearate and isobutyl stearate, and liquid paraffin and silicone oil. be.

<Problems to be Solved by the Invention> However, as mentioned above, the compounds that have been proposed in the past exhibit a certain level of lubricity when they are applied to a material and the material is initially used; There is a problem in that the lubricity is not durable.

The present invention solves the conventional problem of lack of lubricity, which is increasingly required today due to the flattening of material surfaces, and especially of durability in this lubricity. .

<Means to Solve the Problem> However, in view of the above-mentioned situation, the present inventors have worked diligently to obtain a lubricant that can impart lubricity with excellent durability to materials. As a result of research, it was discovered that a specific organosilane compound having a long-chain hydrocarbon group exhibits good lubricity, particularly durability, even under high loads, and the present invention was completed.

That is, the present invention relates to a lubricant for magnetic recording materials characterized by containing one or more organosilane compounds represented by the following general formula (1) or (If).

General formula (1): (R'O(CnHznO)z)p
8iR24p2 General formula (II): (R"0(CnI'(znO)z
St O). -X2 [In general formulas (1) and (II), R1 has 8 carbon atoms
~22 alkyl or alkenyl groups. R2 is an alkyl group having 1 to 3 carbon atoms. X is a di- to tetravalent polyhydric alcohol, right? Organic residues excluding OH groups. t is an integer of 0 or 1 to 5; Om is an integer of 2 to 4; n is an integer of 2 or 3. P is 1-3
an integer of ] In general formulas (1) and (1), monohydric alcohols having a long-chain hydrocarbon group that are the basis of R1 include octyl alcohol, la9yl alcohol, myristyl alcohol, noglymicyl alcohols, There are branched monohydric alcohols such as 2-ethylhexanol, intridecyl alcohol, and instearyl alcohol. In general formula (1), specific examples of polyhydric alcohols that are the basis of Alcohols, trimethylolpronochloride,
There are tri- and tetrahydric alcohols such as glycerin and pentaerythritol, polyalkylene glycols such as diethylene glycol and triethylene glycol, and synthesized using alcohols such as those exemplified above.
Specific examples of the organosilane compound represented by general formula (1) include lauroxytrimethylsilane, oleoxytrimethylsilane, isostearoxytrimethylsilane,
Oleoethoxytrimethylsilane, stearylpropoxytrimethylsilane, oleoethoxyethoxy, trimethylsilane, dioleoxydimethylsilane, tri(n-
octoxy)methylsilane, etc. Similarly, specific examples of the organosilane compound represented by the general formula (1) include ■,2-bis(oleoxydimethylsiloxy)ethane, 1,4-bis(oleoxydimethylsiloxy)butane, 1,6 -bis(lauroxydimethylsiloxy)hexane, 1,2-bis(stearoxypropoquine dimethylsiloxy)ethane, i,t,i-tris(lauroxydimethylsiloxymethylene)propane, 1,2-bis(
Synthesis method including oleoxydimethylsiloxyethoxy)ethane, etc.> Next, a method for synthesizing the organosilane compound in the present invention will be described. The organosilane compound represented by General 24) is produced by, for example, reacting a monohydric alcohol as described above with trimethylmonochloro (or monomethoxy) silane, dimethyldichloro (or dimethoxy) silane, or methyltrichloro (or trimethoxy) silane. The organosilane compound obtained in particular and still having the general formula (...) can be obtained, for example, by reacting a monohydric alcohol as described above with an excess of dimethyldichloro (or dimethoxy)silane, and then reacting the unreacted dimethyl It can be obtained by distilling off dichloro (or dimethoxynosilane) and then adding a polyhydric alcohol as described above to terminate the reaction.More specific examples are as follows. oleyl alcohol 1
7 mol + 3 moles of dimethyldimethoxysilane + 0.3% by weight of potassium hydroxide (based on oleyl alcohol) were placed in a four-way flask, refluxed at 70°C for 4 hours, and the generated methanol and excess dimethyldimethoxysilane were removed under slight vacuum. evaporate to the bottom. Next, 05 mol of ethylene glycol is added and reacted at 100°C for 2 hours, and the methanol produced is distilled off under slightly reduced pressure. After cooling, magnesium silicate is added in an amount 10 times the weight of potassium hydroxide, filtered to remove potassium hydroxide, and an organosilane compound represented by general formula (I) [in general formula (I), is Cl8
H35, R2 is CHs, X is -CH2CH2-1l is Q
, m obtains 2].

<Function, etc.> The lubricant according to the present invention may contain, in addition to the organosilane compound described above, conventionally known lubricant components such as fatty acids and aliphatic esters, to the extent that the effects of the present invention are not impaired. I can do it. Specifically, it is usually used by being added and mixed into a magnetic paint, but there are no particular restrictions on the time of addition or the method of mixing. On this occasion,
The amount used is also not particularly limited, but it is preferably o, i-t relative to the magnetic powder.

Parts by weight, more preferably in the range of 03 to 7 parts by weight.

<Effects of the Invention> The lubricant according to the present invention has the general formula (I
), When the organosilane compound shown in (1) is applied to a material, it can impart lubricity with excellent durability to the material.

<Example> Using each lubricant shown in Table 1 (Examples 1 to 8) and Table 2 (Comparative Examples 1 to 5), the following formulations (all parts by weight) were mixed and mixed in a paint shaker. ,! l) Dispersion was carried out for 8 hours to prepare a paint. -f: Apply each paint onto a polyester film to a thickness of 8μ, dry it,
A tape-shaped sample with a width of 100 degrees was prepared. Each sample prepared was
The humidity was controlled overnight at 0° C. and 65% RH, and the lubricity and durability thereof were evaluated under the same conditions by the following method. The results are shown in each table. ・Composition: Magnetic iron oxide-100, lubricant = 1, arsenic salt copolymer-15, lecithin = 1, polyurethane resin = 8, solvent-2501 Note) Solvent is methyl ethyl ketone /
Toluene = '3/1 (weight ratio) Evaluation: A cylindrical friction body with a surface roughness of 35 and a diameter of 22 m was installed horizontally, and the paint-coated surface of the sample was brought into contact with this friction body so that the contact angle was 90 degrees. and 150 ml at one end of the sample.
A weight of g was attached and hung down, and the other end was kept horizontal and connected to a tension detector. Then, move the friction body at a circumferential speed of 1°Q m7
The friction coefficient μ was calculated by measuring the tension at this time. Friction coefficient 1 minute after starting rotation (μm in the table)
) and the friction coefficient after 5 minutes (μ5 in the table), the lubricity and durability of each lubricant were evaluated.

Table 1 (in the case of Examples) CHa ″ amount Note) S -1: Cl8H350-8i -CH3C
Ha (FH3 S -2: (C18H350-8i -0ya C2H4
CH3 CHa S 3 : (C12H250-3i -0iCsH1
2CHa CHa S -4: (C12H250-8i-OCHz amount C-
C2H5■ CHa? Ha CHa CH3 S -6: (C12H250-8i -0CzH40
-)-C2H+CH3S-7: (C1aHasO-8i-+CH3)2
and 0.3 parts by weight of n-butyl stearate CHaS-8: Cr5HasOC9H60-8i -CH
3CHa Table 2 (for comparative examples) In the case of the lubricants of each example, there is little difference between the μm value and the H5 value, and the lubricant is stable over time and has excellent lubricity. However, in the case of the lubricants of each comparative example, there was a large difference between the μm value and the H5 value, and the friction coefficient increased several times over time, indicating that the lubrication It shows that the nature is not durable.

Patent applicant: Takemoto Yushi Co., Ltd. Agent: Hiroshi Yama, Patent Attorney

Claims (1)

[Scope of Claims] 1. A lubricant for magnetic recording materials, characterized by containing one or more organosilane compounds represented by the following general formula (1) or (It). 2 [In general formula (1) and the same (...), R1 has 8 to 8 carbon atoms
22, an alkyl group or an alkenyl group. R2 has 1 carbon number
~3 alkyl groups. X is a di- to tetravalent polyhydric alcohol.
Organic residues excluding OH groups. l is 0 or an integer from 1 to 5. m
is an integer between 2 and 4. n is an integer of 2 or 3. P is an integer from 1 to 3. ]