Aromatic polyamide and/or aromatic polyimide film and magnetic recording medium having such a film as a base
First Claim
1. A polymeric film comprising a main component selected from the group consisting of an aromatic polyamide, an aromatic polyimide, and their mixtures, said film containing particles, having particle distribution characteristics, at least one surface portion of said film having particle distribution characteristics satisfying both of the following formulae:
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space="preserve" listing-type="equation">10 nm≦
dmax≦
300 nm (1)
space="preserve" listing-type="equation">3≦
ρ
(dmax)/ρ
(dmin)≦
100 (2)where dmax is the depth from said surface of said film at which the particle density has a maximal value;
dmin is the depth from the said surface of said film at which the particle density has a minimal or a minimum value in a range from dmax to 1 μ
m from said surface; and
wherein ρ
(d) is the particle density at each depth.
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Accused Products
Abstract
An aromatic polyamide and/or aromatic polyimide film suitable as a support in a magnetic recording medium excellent in runnability and scratch resistance and good in S/N ratio comprises an aromatic polyamide and/or aromatic polyimide as a main component, with particles present in the film, which film has characteristics which satisfy the following formulae:
10 nm≦dmax≦300 nm (1)
3≦ρ(dmax)/ρ(dmin)≦100 (2)
or
10 nm≦dmax≦300 nm (3)
3≦ρ(dmax)/ρ(d")≦100 (4)
ρ(dmax)/ρ(dmin)>100 (5)
where dmax is the depth from a first surface of the film at which the particle density shows the first maximal value; dmin is the depth at which the particle density shows the first minimal or minimum value in a range from dmax to 1 μm from the said first surface; the linear differential coefficient of the particle density distribution curve has an inflection point at which the quadratic differential coefficient of the particle density distribution curve ia a negative, which inflection point occurs at a depth d", deeper than dmax, and within a range between the depth at which ρ(d) is 4/5 of ρ(dmax), and dmin; and ρ(d) is the particle density at each depth.
24 Citations
12 Claims
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1. A polymeric film comprising a main component selected from the group consisting of an aromatic polyamide, an aromatic polyimide, and their mixtures, said film containing particles, having particle distribution characteristics, at least one surface portion of said film having particle distribution characteristics satisfying both of the following formulae:
-
space="preserve" listing-type="equation">10 nm≦
dmax≦
300 nm (1)
space="preserve" listing-type="equation">3≦
ρ
(dmax)/ρ
(dmin)≦
100 (2)where dmax is the depth from said surface of said film at which the particle density has a maximal value;
dmin is the depth from the said surface of said film at which the particle density has a minimal or a minimum value in a range from dmax to 1 μ
m from said surface; and
wherein ρ
(d) is the particle density at each depth. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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2. A film, which comprises a main component selected from the group consisting of an aromatic polyamide, an aromatic polyimide, and their mixtures, said film containing particles, having particle distribution characteristics measured from a surface portion of said film, said particle distribution characteristics satisfying the following formulae:
-
space="preserve" listing-type="equation">10 nm≦
dmax<
300 nm (3)
space="preserve" listing-type="equation">3≦
ρ
(dmax)/ρ
(d")≦
100 (4)
space="preserve" listing-type="equation">ρ
(dmax)/ρ
(dmin)>
100 (5)where dmax is the depth from a first surface of said film at which the particle density possesses a first maximal value;
wherein dmin is the depth from the said first surface at which the particle density possesses a first minimal or first minimum value in a range from dmax to 1 μ
m from the said first surface; and
wherein the linear differential coefficient of said particle density distribution curve has an inflection point at which the quadratic differential coefficient of said particle density distribution curve is a negative, which inflection point occurs at a depth d" which is deeper than dmax, and within a range between the depth at which ρ
(d) is 4/5 of ρ
(dmax), and dmin; and
wherein ρ
(d) is the particle density at each depth.
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Specification