阅读说明：本技术 具有可调谐的应***化的多层膜 (Multilayer film with tunable strain hardening ) 是由 E·L·李 E·K·马 R·M·帕特尔 P·叶 H-L·吴 A·P·J·斯特约格罗 于 2018-01-19 设计创作，主要内容包括：多层流延膜包括粘附层、剥离层和安置在所述粘附层和所述剥离层之间并且接触所述粘附层和所述剥离层的至少一个芯层。所述粘附层包括超低密度聚乙烯(ULDPE)、丙烯互聚物或其共混物。所述剥离层包括第一线性低密度聚乙烯(第一LLDPE),所述第一LLDPE的密度为0.915到0.938g/cc,并且熔融指数为0.5g/10min到10g/10min。所述芯层中的每个包括第二线性低密度聚乙烯(第二LLDPE),所述第二LLDPE的密度为0.905到0.930g/cc,并且熔融指数为0.5g/10min到10g/10min。以存在于所述多层流延膜中的聚合物的总量计,所述多层流延膜包括3wt％到7wt％的所述低密度聚乙烯(LDPE)。(Multi-layer cast film includes adhesion layer, peeling layer and at least one sandwich layer for being placed between the adhesion layer and the peeling layer and contacting the adhesion layer and the peeling layer.The adhesion layer includes ultra-low density polyethylene (ULDPE), propylene terpolymers or its blend.The peeling layer includes the first linear low density polyethylene (the first LLDPE), and the density of the first LLDPE is 0.915 to 0.938g/cc, and melt index is 0.5g/10min to 10g/10min.Each of described sandwich layer includes the second linear low density polyethylene (the 2nd LLDPE), and the density of the 2nd LLDPE is 0.905 to 0.930g/cc, and melt index is 0.5g/10min to 10g/10min.In terms of the total amount for the polymer being present in the Multi-layer cast film, the Multi-layer cast film includes the low density polyethylene (LDPE) (LDPE) of 3wt% to 7wt%.)

1. a kind of Multi-layer cast film, it includes:

Adhesion layer, the adhesion layer includes:

The density of ultra-low density polyethylene (ULDPE), the ULDPE is 0.895g/cc to 0.915g/cc, and works as basis When ASTM D1238 is measured under 190 DEG C and 2.16kg loads, melt index (I₂) it is 2g/10min to 10g/10min；

Propylene terpolymers, the propylene terpolymers include at least the unit of the derived from propylene of 60wt% and between 1wt% and The unit of derived from ethylene between 40wt%, wherein the density of the propylene terpolymers is 0.840g/cm³To 0.900g/cm³, Highest differential scanning calorimetry (DSC) melting peak temperature is 50.0 DEG C to 120.0 DEG C, when according to ASTM D1238 at 230 DEG C and When the lower measurement of 2.16kg load, melt flow rate (MFR) MFR2 is 1g/10min to 100g/10min, and molecular weight distribution (MWD) Less than 4.0；Or

Its blend；

Peeling layer, the peeling layer include the first linear low density polyethylene (the first LLDPE), the density of the first LLDPE 0.938g/cc, and melt index (I are arrived for 0.915₂) it is 0.5g/10min to 10g/10min；With

At least one sandwich layer being placed between the adhesion layer and the peeling layer, wherein every at least one described sandwich layer A includes the second linear low density polyethylene (the 2nd LLDPE), and the density of the 2nd LLDPE is 0.905 to 0.930g/cc, And melt index (I₂) it is 0.5g/10min to 10g/10min；

Wherein:

One or more of the adhesion layer, the peeling layer or at least one described sandwich layer further include low density polyethylene Alkene, the density of the low density polyethylene (LDPE) are 0.918g/cc to 0.931g/cc, and melt index (I₂) it is 0.15g/10min To 6g/10min；

In terms of the total amount for the polymer being present in the Multi-layer cast film, the Multi-layer cast film includes 3wt% to 7wt%'s The low density polyethylene (LDPE) (LDPE)；

The Multi-layer cast film is limited by least one of following characteristic:

As according to measured by ASTM D882, limit of stretch elongation in the direction of the machine is less than 300%；

Natural draw ratio (NDR) is less than 250%；Or

As according to measured by ASTM D4649, Highlight ultimate elongation is less than 300%；And

According to ASTM D882, for the film with a thickness of 10 microns or thicker, the Multi-layer cast film is shown at the second surrender Machine direction stretch stress be at least 21.0 MPa.

2. Multi-layer cast film according to claim 1, wherein in terms of the total amount for the polymer being present in the layer, it is described LDPE is present in the amount in any one layer no more than 20wt%.

3. Multi-layer cast film according to any one of the preceding claims, wherein with the polymerization being present in the peeling layer The total amount meter of object, the peeling layer include the LDPE of 3wt% to 20wt%.

4. Multi-layer cast film according to any one of the preceding claims, wherein when there are two or more sandwich layers, In terms of the total amount for the polymer being present in the sandwich layer, at least one of described sandwich layer includes the institute of 3wt% to 20wt% State LDPE.

5. Multi-layer cast film according to any one of the preceding claims, wherein the adhesion layer further includes third line Property low density polyethylene (LDPE) (the 3rd LLDPE), the density of the 3rd LLDPE is 0.905 to arrive 0.930g/cc, and melt index (I₂) it is 0.5g/10min to 10g/10min.

6. Multi-layer cast film according to claim 5, wherein in first LLDPE, the 2nd LLDPE and the 3rd LLDPE Two or more are different from each other.

7. Multi-layer cast film according to claim 5, wherein first LLDPE, the 2nd LLDPE and the third The MWD of LLDPE is 3.5 to 5.0, and comonomer distribution breadth index (CDBI) is less than 70%.

8. the Multi-layer cast film according to claim 5 to 7, wherein the first LLDPE of the peeling layer is ethylene-fourth Alkene copolymer, and the 2nd LLDPE at least one sandwich layer described in adjacent with the peeling layer be ethylene/ C₅-C₂₀Alpha-olefin interpolymers.

9. the Multi-layer cast film according to claim 5 to 8, wherein the 3rd LLDPE of the adhesion layer is ethylene-fourth Alkene copolymer, and the 2nd LLDPE at least one sandwich layer described in adjacent with the adhesion layer be ethylene/ C₅-C₂₀Alpha-olefin interpolymers.

10. the Multi-layer cast film according to claim 5 to 9, wherein the film includes three sandwich layers, one of inner sandwich layer Comprising ethylene-butene copolymer, and multiple outer sandwich layers include ethylene/C₅-C₂₀Alpha-olefin interpolymers.

11. Multi-layer cast film according to claim 10 the, wherein melt index (I of the ethylene-butene copolymer₂) In In the range of 0.5g/10min to 10g/10min.

12. Multi-layer cast film described in 0 or 11 according to claim 1 the, wherein ethylene/C₅-C₂₀Alpha-olefin interpolymers it is close Degree is 0.905g/cc to 0.930g/cc.

13. Multi-layer cast film described in any one of 0 to 12 according to claim 1 the, wherein ethylene/C₅-C₂₀Alpha-olefin is mutual Melt index (the I of polymers₂) in the range of 0.25g/10min to 10g/10min.

14. Multi-layer cast film according to any one of the preceding claims, wherein the sandwich layer with a thickness of the multilayer 50% to the 90% of the overall thickness of film.

15. Multi-layer cast film according to any one of the preceding claims, wherein the multilayer film with a thickness of 5 μm to 15 μm。

Technical field

Embodiment of the disclosure relates generally to multilayer film, and relate in particular to include LDPE multilayer film.

Background technique

Multilayer film may include the film such as casting films or blown film, may include ensiling packaging, stretch package and surface protection Film.Linear low density polyethylene (LLDPE) and/or high density polyethylene (HDPE) (HDPE) be widely used in production have high tensile and The multilayer film of high impact.Optimize film stretching intensity by polymer blend and the conventional of yield strength attempts to have generated With lower film, there is the yield strength improved, but its impact strength is lower than a kind of component preparation by using in the blend Film.

Therefore, it is necessary to develop that there is the strain hardening and yield strength improved, while film being made to keep stretchable multilayer film.

Summary of the invention

Detailed description of the invention

Fig. 1 is the figure for describing the tensile stress (longitudinal axis) of film become with stretching % (horizontal axis) of comparative sample A and sample 1 Shape；

Fig. 2 is the figure for describing the tensile stress (longitudinal axis) of film become with stretching % (horizontal axis) of sample 2-5；With

Fig. 3 is the tensile stress become with stretching % (horizontal axis) for describing the film of comparative sample B and C and sample 6 and 7 The figure of (longitudinal axis).

Embodiment is related to Multi-layer cast film, and it includes low density polyethylene (LDPE) (LDPE), the density of the LDPE is 0.918g/ Cc to 0.931g/cc, and melt index (I₂) it is 0.15g/10min to 6g/10min.Multilayer film can produce improved strain Hardening and yield strength.

According to one embodiment, Multi-layer cast film includes adhesion layer, peeling layer and is placed between adhesion layer and peeling layer At least one sandwich layer.Adhesion layer includes ultra-low density polyethylene (ULDPE), propylene terpolymers or its blend.ULDPE's is close Degree is 0.895g/cc to 0.915g/cc, and when being measured under 190 DEG C and 2.16kg loads according to ASTM D1238, melting Index (I₂) it is 2g/10min to 10g/10min.Propylene terpolymers include at least unit of the derived from propylene of 60wt% and Jie The unit of derived from ethylene between 1wt% and 40wt%, and its density is 0.840g/cm³To 0.900g/cm³, highest Differential scanning calorimetry (DSC) melting peak temperature is 50.0 DEG C to 120.0 DEG C, when according to ASTM D1238 at 230 DEG C and Under 2.16kg load when measurement, melt flow rate (MFR) MFR₂For 1g/10min to 100g/10min, and molecular weight distribution (MWD) Less than 4.0.Peeling layer includes the first linear low density polyethylene (the first LLDPE), and density is 0.915 to 0.938g/cc, and And melt index is 0.5g/10min to 10g/10min.Each of sandwich layer includes the second linear low density polyethylene (second LLDPE), density is 0.905 to 0.930g/cc, and melt index is 0.5g/10min to 10g/10min.Adhesion layer, stripping One or more of absciss layer or at least one sandwich layer further comprise low density polyethylene (LDPE), and density arrives for 0.918g/cc 0.931g/cc, and melt index (I₂) it is 0.15g/10min to 6g/10min.To be present in the polymerization in Multi-layer cast film The total amount meter of object, Multi-layer cast film include the low density polyethylene (LDPE) (LDPE) of 3wt% to 7wt%.Multi-layer cast film is by following spy Property at least one of limit: as according to measured by ASTM D882, limit of stretch elongation in the direction of the machine is less than 300%；Natural draw ratio (NDR) is less than 250%；Or as according to measured by ASTM D4649, Highlight ultimate elongation is less than 300%.In addition, for the film with a thickness of 10 microns or thicker, Multi-layer cast film shows to bend second according to ASTM D882 Machine direction stretch intensity at clothes is greater than 21.0MPa.