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US4075050A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of making synthetic paper

Assignee: Mitsubishi Chemical Corp
•
Filing: 1975-12-17
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Granted: 1978-02-21
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Expires: 1995-12-17
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Abstract

Abstract A laminated structure forming a synthetic paper made of a base or backing film layer made of a thermoplastic resin in a biaxially oriented state. A paper-like film layer is laminated to the base film layer and comprises a thermoplastic resin having 0.5 to 65% by weight of particles of a fine, inorganic filler dispersed in the resin thereof substantially uniformly. The paper-like film layer is in an uniaxially oriented state and has microvoids dispersed therein formed by stretching the laminated films in a heated state. The microvoids comprise microvoids open to a surface of the paper-like film layer free of the base film layer and include microvoids, open and closed, distributed in the paper-like film layer defining therein a cellular, fibrous structure. The two films are formed from thermoplastic resinous compositions in which the components of each composition are well admixed and particles of a fine filler are uniformly distributed in the thermoplastic resin of the paper-like film layer to obtain, as much as possible, microvoids distributed therein uniformly. After the base film layer is formed, it is stretched in a heated state in a machine for longitudinal direction to orient the film uniaxially. The paper-like layer is laminated under pressure on one surface of the base film layer while in a melted state and the resulting laminated structure is stretched transversely to at least 2.5 times the original transverse dimension of the portion of film being stretched between grippers of a stretching machine. This orients the base film layer biaxially and the paper-like film layer uniaxially. The stretching must be sufficient for the stretching and particles of filler to develop microvoids in the paper-like film layer rendering it a cellular and fibrous structure.

Inventors

  • 👤 Masanori Takashi
  • 👤 Mitsuo Yoshiyasu

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 20:31
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C55/00; B29C55/02; B29C55/023; B29C55/026; B32B27/18; B32B27/20; B32B27/205; B32B38/00; B32B38/0012; B32B2038/0028; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/70; B32B2307/75; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249986

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 248 words
A method of producing a synthetic paper-like laminate comprising, providing a base film layer made of a thermoplastic resin, uniaxially orienting the base film layer, laminating on said base film layer a paper-like film layer made of a thermoplastic resin having more than 25% and no more than 65% by weight of particles of a fine inorganic filler substantially uniformly distributed therein thereby to form a laminate, the weight percentage of said inorganic filler being dependent on the weight of the resin plus the filler, stretching while in a heated state the laminate in a transverse direction to biaxially orient the base film layer and uniaxially orient the paper-like film layer including stretching the laminate in the transverse direction from 7 to 16 times greater than the original transverse dimension of said films in the last-mentioned direction to develop microvoids having a void proportion of from 10% to 65% in said paper-like film layer in conjunction with said particles of filler distributed internally in the paper-like layer as comminicating and independent microvoids to develop fibrous-like portions of the resin thereof among the microvoids interiorly of said paper-like film layer to define therein a cellular, fibrous structure, said stretching including developing of microvoids open to the surface of said paper-like film layer free of said base film layer and distributed throughout said surface, ceasing said stretching, and setting said resin after stretching maintaining the internal microvoids including the last-mentioned microvoids open to said surface upon cessation of said stretching.
Claim 2
Independent Claim 248 words
A method of producing a synthetic paper-like laminate comprising, providing a base film layer made of a thermoplastic resin, uniaxially orienting the base film layer, laminating on said base film layer a paper-like film layer made of a thermoplastic resin having more than 25% and no more than 65% by weight of particles of a fine inorganic filler substantially uniformly distributed therein thereby to form a laminate, the weight percentage of said inorganic filler being dependent on the weight of the resin plus the filler, stretching while in a heated state the laminate in a transverse direction to biaxially orient the base film layer and uniaxially orient the paper-like film layer including stretching the laminate in the transverse direction from 7 to 16 times greater than the original transverse dimension of said films in the last-mentioned direction to develop microvoids having a void proportion of from 10% to 65% in said paper-like film layer in conjunction with said particles of filler distributed internally in the paper-like layer as comminicating and independent microvoids to develop fibrous-like portions of the resin thereof among the microvoids interiorly of said paper-like film layer to define therein a cellular, fibrous structure, said stretching including developing of microvoids open to the surface of said paper-like film layer free of said base film layer and distributed throughout said surface, ceasing said stretching, and setting said resin after stretching maintaining the internal microvoids including the last-mentioned microvoids open to said surface upon cessation of said stretching.
Claim 3
Dependent Claim 30 words
A method of producing a synthetic paper-like laminate according to claim 1, including applying an electrostatic charge to said synthetic laminate to render said paper-like layer more attractive to ink.
Claim 4
Dependent Claim 39 words
A method of producing a synthetic paper-like laminate according to claim 1, in which said base film layer is extruded, cooled immediately afterward and stretched while in a heated state in a longitudinal direction to orient the resin thereof.
Claim 5
Dependent Claim 36 words
A method of producing a synthetic paper-like laminate according to claim 1, in which said laminate is preheated and then stretched transversely to biaxially orient the base film layer and uniaxially orient the paper-like film layer.

References Cited (Backward Citations)

US3281347A Cited
US3503842A Cited
US3515626A Cited
US3515625A Cited
US3799828A Cited
US3669728A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-02-20 1981-08-22 1982-02-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-02-20 1985-08-22 1986-02-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-02-20 1989-08-22 1990-02-21 $7700.00 Window Closed / Lapsed

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