High isotactic PP resin with wide melting distribution having improved BOPP film properties and easy processing characteristics

Patent metadata

Field	Value
Publication number	US-9487634-B2
Application number	US-201314440844-A
Country	US
Kind code	B2
Filing date	Nov 6, 2013
Priority date	Nov 16, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The present invention relates to a new biaxially oriented polypropylene (BOPP) film, a process for the preparation of such film as well as the use of a polypropylene for the preparation of such film and an article comprising such film.

First claim

The invention claimed is:

1. Biaxially oriented polypropylene (BOPP) film comprising: a polypropylene (PP) having a residual crystallinity f RC of ≦0.4 at a temperature (T) being 1° C. below the melting temperature (T m ) of the polypropylene (PP) [T=T m −1].

2. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the polypropylene (PP) has a residual crystallinity f RC of ≦0.3 at the melting temperature (T m ) of the polypropylene (PP).

3. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film comprises a polypropylene (PP) comprising:
(a) crystalline fractions crystallizing in the temperature range of
(i) 150 to 160° C., and
(ii) 160 to 170° C.,

wherein the amount of the two crystalline fractions [wt. % ] differs from each other of more than 10.0 wt. %, wherein further said fractions are determined by the stepwise isothermal segregation technique (SIST), and/or
(b) crystalline fractions crystallizing in the temperature range of
(i) 160 to 170 ° C., and
(ii) 170 to 180 ° C.,

wherein the amount of the two crystalline fractions [wt. % ] differs from each other of not more than 7.0 wt. %, wherein further said fractions are determined by the stepwise isothermal segregation technique (SIST), and/or
(c) crystalline fractions crystallizing above 160° C. of more than 63.0 wt. %, wherein said fractions are determined by the stepwise isothermal segregation technique (SIST).

4. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film comprises a polypropylene (PP) comprising:
(a) crystalline fractions crystallizing in the temperature range of below 120° C. in an amount of not more than 1.0 wt. %, wherein said fractions are determined by the stepwise isothermal segregation technique (SIST), and/or
(b) crystalline fractions crystallizing in the temperature range of below 150° C. in an amount of not more than 16.0 wt. %, wherein said fractions are determined by the stepwise isothermal segregation technique (SIST), and/or
(c) crystalline fractions crystallizing above 180° C. in an amount of not more than 1.0 wt. %, wherein said fractions are determined by the stepwise isothermal segregation technique (SIST).

5. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film comprises a polypropylene (PP) having:
(a) a melting temperature (T m ) measured by differential scanning calorimetry (DSC) of at least 160 ° C., and/or
(b) a crystallization temperature (T c ) measured by differential scanning calorimetry (DSC) of at least 115° C.

6. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film comprises a polypropylene (PP) having:
(a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 of≦7.0 g/10 min, and/or
(b) a xylene cold soluble fraction (XCS) determined at 23° C. according ISO 6427 of≧2.0 wt. %, and/or
(c) an mmmm pentad concentration of≧95.0% determined by NMR-spectroscopy, and/or
(d) 2,1-erythro reciodefects of below 1.0% determined by 13 C-NMR spectroscopy.

7. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film comprises a polypropylene (PP) being a propylene homopolymer (H-PP).

8. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the biaxially oriented polypropylene (BOPP) film has been prepared at a yield force in machine direction of≦20 N.

9. Process for the preparation of a biaxially oriented polypropylene (BOPP) film, the process comprising at least the steps of:
(a) providing a polypropylene (PP) as defined in claim 1 , and
(b) stretching the polypropylene of step a) in machine direction and transverse direction.

10. Biaxially oriented polypropylene (BOPP) film according to claim 1 , wherein the polypropylene (PP) has:
(a) a crystallinity of>61.5 wt. %, and
(b) a shrinkage of<2.2%,
when drawn at a draw ratio in machine direction and transverse direction of 5.0 and as drawing temperature (Tdraw) being 1° C. below the melting temperature (T m ) of the polypropylene (PP) [T draw =T m −1].

11. Biaxially oriented polypropylene (BOPP) film comprising: a polypropylene (PP), said polypropylene (PP) has:
(a) a crystallinity of>61.5 wt. %, and
(b) a shrinkage of<2.2%,
when drawn at a draw ratio in machine direction and transverse direction of 5.0 and as drawing temperature (Tdraw) being 1° C. below the melting temperature (T m ) of the polypropylene (PP) [T draw =T m −1].

Assignees

• Borealis Ag

Inventors

• Neissl Wolfgang
• Gloger Dietrich
• Potter Gregory
• Tranchida Davide

Classifications

• B29C55/005

  characterised by the choice of materials · CPC title

• C08F2/34

  Polymerisation in gaseous state · CPC title

• C08F2500/15

  Isotactic · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08F2/02

  Polymerisation in bulk · CPC title