Claims
- 1. A packaging bag comprising an outer bag made of paper and an inner bag made of a monoaxially or biaxially stretched film having a heat shrinkage of 20% or more in one of the longitudinal and transverse directions and 60% or more in the other direction and comprising 100 to 50 parts by weight of a linear polyethylene having a density of 0.910 to 0.965 g/cm.sup.3, a melt index of 2 g/10 min or below and a fluidity ratio of 120 or below; 0 to 50 parts by weight of a branched low-density polyethylene having a melt index of 2 g/10 min or below, a fluidity ratio of 70 or below and a density of 0.930 g/cm.sup.3 or below; and 0.0001 to 0.1 part by weight of a radical initiator as an optional component.
- 2. A packaging bag according to claim 1, wherein said monoaxially stretched film is produced by a process comprising the steps of:
- forming a non-stretched film or sheet by blow-extruding a composition comprising 100 to 50 parts by weight of a linear polyethylene having a density of 0.910 to 0.965 g/cm.sup.3, a melt index of 2 g/10 min. or below and a fluidity ratio of 50 or below; 0 to 50 parts by weight of a branched low-density polyethylene having a density of 0.930 g/cm.sup.3 or below, a melt index of 2 g/10 min. or below and a fluidity ratio of 70 or below; and 0.0001 to 0.1 part by weight of a radical initiator as an optional component, under the condition of blow-up ratio of 2 to 8 and frost line height of 2 to 50 times the die diameter while or after decomposing said radical initiator if present and reacting with said linear polyethylene and branched low-density polyethylene, and
- monoaxially stretching the non-stretched film or sheet 1.5 to 8 times in the longitudinal direction at a temperature of Tm-70 to Tm-20.degree. C., wherein Tm is the melting point of said composition or a modified composition obtained from said composition by the action of said radical initiator.
- 3. A packaging bag according to claim 1, wherein said monoaxially or biaxially stretched film is produced by a process comprising the steps of:
- forming a non-stretched film or sheet by blown film forming method or T-die method from a composition comprising 100 to 50 parts by weight of a linear polyethylene having a density of 0.910 to 0.965 g/cm.sup.3, a melt index of 2 g/10 min. or below and a fluidity ratio of 50 or below; 0 to 50 parts by weight of a branched low-density polyethylene having a density of 0.930 g/cm.sup.3 or below, a melt index of 2 g/10 min. or below and a fluidity ratio of 70 or below; and 0.0001 to 0.1 part by weight of a radical initiator as an optional component, under the condition of a resin temperature from 150.degree. to 250.degree. C. and a draft ratio of 1 to 50 while or after decomposing said radical initiator and reaction with said linear polyethylene and branched low-density polyethylene, and
- monoaxially or biaxially stretching the non-stretched film or sheet 1.2 to 9 times the original area at a temperature of Tm-70 to Tm-5.degree. C., wherein Tm is the melting point of said composition or a modified composition obtained from said composition by the action of said radical initiator.
- 4. The packaging bag according to claim 3, wherein said monoaxially or biaxially stretching is carried out by monoaxially stretching said non-stretched film or sheet 1.2 to 9 times in the transverse direction or biaxially stretching said non-stretched film or sheet 1.2 to 3 times in the longitudinal direction and 3 to 7.5 times in the transverse direction.
- 5. A packaging bag according to claim 1, wherein said monoaxially stretched film is produced by a process comprising the steps of:
- forming a non-stretched film or sheet by blow-extruding a composition comprising 100 to 50 parts by weight of a linear polyethylene having a density of 0.91 to 0.965 g/cm.sup.3, a melt index of 2 g/10 min. or below a fluidity ratio of higher than 50 and not higher than 120 and 0 to 50 parts by weight of a branched low-density polyethylene having a density of 0.930 g/cm.sup.3 or below, a melt index of 2 g/10 min. or below and a fluidity ratio of 70 or below, under the conditions of blow-up ratio of 2 to 8 and frost line height of 2 to 50 times the die diameter, and
- monoaxially stretching said non-stretched film or sheet 1.5 to 8times in the film take-up direction at a temperature of Tm-70.degree. C. to Tm-20.degree. C. wherein Tm is the melting point of said composition.
Priority Claims (5)
Number |
Date |
Country |
Kind |
62-174527 |
Jul 1987 |
JPX |
|
62-204539 |
Aug 1987 |
JPX |
|
62-205786 |
Aug 1987 |
JPX |
|
63-19054 |
Jan 1988 |
JPX |
|
63-151980 |
Jun 1988 |
JPX |
|
Parent Case Info
This is a divisional of copending application(s) Ser. No. 07/217,930 filed on 7/12/88 now abandoned.
US Referenced Citations (17)
Foreign Referenced Citations (14)
Number |
Date |
Country |
0021635 |
Jan 1981 |
EPX |
0048227 |
Dec 1982 |
EPX |
58-126141 |
Jul 1983 |
JPX |
59-178221 |
Oct 1984 |
JPX |
60-072715 |
Apr 1985 |
JPX |
60-180825 |
Sep 1985 |
JPX |
60-183132 |
Sep 1985 |
JPX |
59-18121 |
Nov 1985 |
JPX |
60-245541 |
Dec 1985 |
JPX |
60-257232 |
Dec 1985 |
JPX |
60-275232 |
Dec 1985 |
JPX |
61-229529 |
Oct 1986 |
JPX |
61-273930 |
Dec 1986 |
JPX |
62-039226 |
Feb 1987 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Encyclopedia of Polymer Science & Engineering, 2nd Edition, Wiley-International, 1987, vol. 7, pp. 98-100. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
217930 |
Jul 1988 |
|