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Title:
MULTILAYER FILMS
Document Type and Number:
WIPO Patent Application WO/2019/213192
Kind Code:
A1
Abstract:
A multilayer film includes a first polypropylene skin layer and a second polypropylene skin layer. The multilayer film includes a core layer between the first polypropylene skin layer and the second polypropylene skin layer. The core layer includes polypropylene and a foam agent.

Inventors:
CHOU TZU-YU (US)
CHUANG MING HUA (TW)
HU YU FENG (TW)
OU HSU FONG (TW)
Application Number:
PCT/US2019/030105
Publication Date:
November 07, 2019
Filing Date:
May 01, 2019
Export Citation:
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Assignee:
CORNING INC (US)
International Classes:
B32B27/08; B32B27/32
Domestic Patent References:
WO2005032815A12005-04-14
Foreign References:
US20130327476A12013-12-12
US5858552A1999-01-12
US4828915A1989-05-09
US20050136235A12005-06-23
Attorney, Agent or Firm:
HARDEE, Ryan T (US)
Download PDF:
Claims:
What is claimed is:

1. A multilayer film comprising:

a first polypropylene skin layer;

a second polypropylene skin layer; and

a core layer between the first polypropylene skin layer and the second polypropylene skin layer, the core layer comprising polypropylene and a foam agent.

2. The multilayer film of claim 1, wherein the core layer comprises low density polyethylene (LDPE).

3. The multilayer film of claim 1, wherein the multilayer film comprises a thickness between 100 pm and 165 pm.

4. The multilayer film of claim 1, wherein the multilayer film comprises a weight between 60 g/m2 and 90 g/m2.

5. The multilayer film of claim 1, wherein the multilayer film comprises a weight per thickness between 0.4 g/m2-pm and 0.6 g/m2-pm.

6. The multilayer film of claim 1, wherein the first polypropylene skin layer comprises a thickness between 15 pm and 20 pm,

the second polypropylene skin layer comprises a thickness between 15 pm and 20 pm, and

the core layer comprises a thickness between 70 pm and 110 pm.

7. The multilayer film of claim 1, wherein the core layer is directly bonded to the first polypropylene skin layer and the second polypropylene skin layer.

8. A multilayer film comprising:

a first skin layer comprising polypropylene and a powder;

a second skin layer comprising polypropylene and a powder; and a polypropylene core layer between the first skin layer and the second skin layer.

9. The multilayer film of claim 8, wherein the powder comprises a gel.

10. The multilayer film of claim 8, wherein the multilayer film comprises a thickness between 100 pm and 135 pm.

11. The multilayer film of claim 8, wherein the multilayer film comprises a weight between 60 g/m2 and 70 g/m2.

12. The multilayer film of claim 8, wherein the multilayer film comprises a weight per thickness between 0.5 g/m2-pm and 0.6 g/m2-pm.

13. The multilayer film of claim 8, wherein the first skin layer comprises a thickness between 15 pm and 20 pm,

the second skin layer comprises a thickness between 15 pm and 20 pm, and the core layer comprises a thickness between 70 pm and 110 pm.

14. The multilayer film of claim 8, wherein the core layer is directly bonded to the first skin layer and the second skin layer.

15. A multilayer film comprising:

a first polypropylene skin layer;

a second polypropylene skin layer; and

a core layer between the first polypropylene skin layer and the second polypropylene skin layer, the core layer comprising polypropylene and a powder.

16. The multilayer film of claim 15, wherein the powder comprises a gel.

17. The multilayer film of claim 15, wherein the multilayer film comprises a thickness between 100 pm and 140 pm.

18. The multilayer film of claim 15, wherein the multilayer film comprises a weight between 60 g/m2 and 70 g/m2.

19. The multilayer film of claim 15, wherein the multilayer film comprises a weight per thickness between 0.5 g/rrf-pm and 0.6 g/rrr-pm.

20. The multilayer film of claim 15, wherein the first polypropylene skin layer comprises a thickness between 15 pm and 20 pm,

the second polypropylene skin layer comprises a thickness between 15 pm and 20 pm, and

the core layer comprises a thickness between 70 pm and 110 pm.

Description:
MULTILAYER FILMS

BACKGROUND

Cross-Reference to Related Application

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 62/665625 filed on May 2, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

Field

[0002] The present disclosure relates generally to multilayer films. More particularly, it relates to multilayer films for protecting glass sheets.

Technical Background

[0003] Bare glass sheets are typically shipped from one location where the glass sheets are manufactured to another location where the glass sheets are used in a product. To prevent damage, such as breaking and/or scratching, the glass sheets are typically packed using a packing material. The packing material may also be used to keep the glass sheets clean prior to use.

SUMMARY

[0004] Some embodiments of the present disclosure relate to a multilayer film. The multilayer film includes a first polypropylene skin layer and a second polypropylene skin layer. The multilayer film includes a core layer between the first polypropylene skin layer and the second polypropylene skin layer. The core layer includes polypropylene and a foam agent.

[0005] Yet other embodiments of the present disclosure relate to a multilayer film. The multilayer film includes a first skin layer including polypropylene and a powder and a second skin layer including polypropylene and a powder. The multilayer film includes a polypropylene core layer between the first skin layer and the second skin layer. [0006] Yet other embodiments of the present disclosure relate to a multilayer film. The multilayer film includes a first polypropylene skin layer and a second polypropylene skin layer. The multilayer film includes a core layer between the first polypropylene skin layer and the second polypropylene skin layer. The core layer includes polypropylene and a powder.

[0007] The multilayer films disclosed herein may be used to protect glass sheets. The multilayer films may protect the surface quality of glass sheets, for example, by protecting the surfaces of the glass sheets from scratches. In addition, once the multilayer films are removed from the glass sheets, the surfaces of the glass sheets are clean (e.g., low particle density and no material related residue). Further, packing and unpacking equipment may not need to be modified to use the multilayer films.

[0008] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0009] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 depicts a cross-sectional view of an exemplary multilayer film including a foam agent;

[0011] FIG. 2 depicts a cross-sectional view of an exemplary multilayer film including a powder in the skin layers;

[0012] FIG. 3 depicts a cross-sectional view of an exemplary multilayer film including a powder in the core layer; and

[0013] FIG. 4 depicts a cross-sectional view of an exemplary stack of glass sheets protected by multilayer films. DETAILED DESCRIPTION

[0014] Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0015] Ranges can be expressed herein as from“about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0016] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, vertical, horizontal - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0017] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus, specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0018] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to“a” component includes aspects having two or more such components, unless the context clearly indicates otherwise. [0019] Referring now to FIG. 1, a cross-sectional view of an exemplary multilayer film 100 is depicted. Multilayer film 100 may include a first polypropylene skin layer l02a, a second polypropylene skin layer l02b, and a core layer 104 between the first polypropylene skin layer l02a and the second polypropylene skin layer l02b. The core layer 104 may include polypropylene 106 and a foam agent 108 distributed within the polypropylene 106. Core layer 104 may also include low density polyethylene (LDPE) in addition to the polypropylene. Core layer 104 may be directly bonded to first polypropylene skin layer l02a at an interface 112 and to second polypropylene skin layer l02b at an interface 114. In certain exemplary embodiments, first polypropylene skin layer l02a and second polypropylene skin layer l02b may be laminated to core layer 104.

[0020] Multilayer film 100 has a bottom surface 110 and a top surface 116 opposite to the bottom surface 110. The bottom surface 110 and the top surface 116 may have dimensions based upon the glass sheet(s) onto which multilayer film 100 is to be applied. The dimensions of the bottom surface 110 and the top surface 116 may be selected to form multilayer film 100 having a suitable shape (e.g., rectangular, circular, hexagonal, etc.) to match the shape of the glass sheet(s) to be protected. Multilayer film 100 may have a thickness between about 100 pm and about 165 pm from the bottom surface 110 to the top surface 116. Multilayer film 100 may have a weight between about 60 g/m 2 and about 90 g/m 2 . Multilayer film 100 may have a weight per thickness between about 0.4 g/m 2 -pm and about 0.6 g/m 2 -pm.

[0021] First polypropylene skin layer l02a may have a thickness between about 15 pm and about 20 pm from the bottom surface 110 (i.e., the bottom surface of first polypropylene skin layer l02a) to the interface 112 between first polypropylene skin layer l02a and core layer 104. Likewise, second polypropylene skin layer l02b may have a thickness between about 15 pm and about 20 pm from the interface 114 between second polypropylene skin layer l02b and core layer 104 to the top surface 116 (i.e., the top surface of second polypropylene skin layer l02b). Core layer 104 may have a thickness between about 70 pm and about 110 pm from interface 112 between first polypropylene skin layer l02a and core layer 104 to interface 114 between core layer 104 and second polypropylene skin layer l02b.

[0022] Foam agent 108 in core layer 104 may prevent damage (e.g., scratches) to a glass sheet upon which multilayer film 100 is applied by providing a cushioning function. Further, polypropylene skin layers l02a and l02b do not leave a residue on the glass sheets when multilayer film 100 is removed. Since multilayer film 100 has a thickness and a stiffness similar to paper used in some glass sheet packing and unpacking equipment, multilayer film 100 may be substituted for the paper without modification to the packing and unpacking equipment. By using multilayer film 100 in place of paper or other types of films, the surface quality of the glass sheets after unpacking may be improved.

[0023] FIG. 2 depicts a cross-sectional view of an exemplary multilayer film 200. Multilayer film 200 may include a first skin layer 202a, a second skin layer 202b, and a polypropylene core layer 208 between the first skin layer 202a and the second skin layer 202b. First skin layer 202a may include polypropylene 204 and a powder 206 distributed within the polypropylene 204. Likewise, second skin layer 202b may include polypropylene 204 and a powder 206 distributed within the polypropylene. Powder 204 may be beads and include a gel or another suitable material. Polypropylene core layer 208 may be directly bonded to first skin layer 202a at an interface 212 and to second skin layer 202b at an interface 214. In certain exemplary embodiments, first skin layer 202a and second skin layer 202b may be laminated to polypropylene core layer 208.

[0024] Multilayer film 200 has a bottom surface 210 and a top surface 216 opposite to the bottom surface 210. The bottom surface 210 and the top surface 216 may have dimensions based upon the glass sheet(s) onto which multilayer film 200 is to be applied. The dimensions of the bottom surface 210 and the top surface 216 may be selected to form multilayer film 200 having a suitable shape (e.g., rectangular, circular, hexagonal, etc.) to match the shape of the glass sheet(s) to be protected. Multilayer film 200 may have a thickness between about 100 pm and about 135 pm from the bottom surface 210 to the top surface 216. Multilayer film 200 may have a weight between about 60 g/m 2 and about 70 g/m 2 . Multilayer film 200 may have a weight per thickness between about 0.5 g/m 2 -pm and about 0.6 g/m 2 -pm.

[0025] First skin layer 202a may have a thickness between about 15 pm and about 20 pm from the bottom surface 210 (i.e., the bottom surface of first skin layer 202a) to the interface 212 between first skin layer 202a and polypropylene core layer 208. Likewise, second skin layer 202b may have a thickness between about 15 pm and about 20 pm from the interface 214 between second skin layer 202b and polypropylene core layer 208 to the top surface 216 (i.e., the top surface of second skin layer 202b). Polypropylene core layer 208 may have a thickness between about 70 pm and about 110 pm from interface 212 between first skin layer 202a and polypropylene core layer 208 to interface 214 between polypropylene core layer 208 and second skin layer 202b. [0026] Powder 206 in first skin layer 202a and second skin layer 202b may prevent damage (e.g., scratches) to a glass sheet upon which multilayer film 200 is applied by providing a cushioning function. Further, skin layers 202a and 202b do not leave a residue on the glass sheets when multilayer film 200 is removed. Since multilayer film 200 has a thickness and a stiffness similar to paper used in some glass sheet packing and unpacking equipment, multilayer film 200 may be substituted for the paper without modification to the packing and unpacking equipment. By using multilayer film 200 in place of paper or other types of films, the surface quality of the glass sheets after unpacking may be improved.

[0027] FIG. 3 depicts a cross-sectional view of an exemplary multilayer film 300. Multilayer film 300 includes a first polypropylene skin layer 302a, a second polypropylene skin layer 302b, and a core layer 304 between the first polypropylene skin layer 302a and the second polypropylene skin layer 302b. The core layer 304 includes polypropylene 306 and a powder 308 distributed within the polypropylene 306. Powder 308 may be beads and include a gel or another suitable material. Core layer 304 may be directly bonded to first polypropylene skin layer 302a at an interface 312 and to second polypropylene skin layer 302b at an interface 314. In certain exemplary embodiments, first polypropylene skin layer 302a and second polypropylene skin layer 302b may be laminated to core layer 304.

[0028] Multilayer film 300 has a bottom surface 310 and a top surface 316 opposite to the bottom surface 310. The bottom surface 310 and the top surface 316 may have dimensions based upon the glass sheet(s) onto which multilayer film 300 is to be applied. The dimensions of the bottom surface 310 and the top surface 316 may be selected to form multilayer film 300 having a suitable shape (e.g., rectangular, circular, hexagonal, etc.) to match the shape of the glass sheet(s) to be protected. Multilayer film 300 may have a thickness between about 100 pm and about 140 pm from the bottom surface 310 to the top surface 316. Multilayer film 300 may have a weight between about 60 g/m 2 and about 70 g/m 2 . Multilayer film 300 may have a weight per thickness between about 0.5 g/m 2 -pm and about 0.6 g/m 2 -pm.

[0029] First polypropylene skin layer 302a may have a thickness between about 15 pm and about 20 pm from the bottom surface 310 (i.e., the bottom surface of first polypropylene skin layer 302a) to the interface 312 between first polypropylene skin layer 302a and core layer 304. Likewise, second polypropylene skin layer 302b may have a thickness between about 15 pm and about 20 pm from interface 314 between first polypropylene skin layer 302a to the top surface 316 (i.e., the top surface of second polypropylene skin layer 302b). Core layer 304 may have a thickness between about 70 mih and about 110 mih from interface 312 between first polypropylene skin layer 302a and core layer 304 to interface 314 between core layer 304 and second polypropylene skin layer 302b.

[0030] Powder 308 in core layer 304 may prevent damage (e.g., scratches) to a glass sheet upon which multilayer film 300 is applied by providing a cushioning function. Further, polypropylene skin layers 302a and 302b do not leave a residue on the glass sheets when multilayer film 300 is removed. Since multilayer film 300 has a thickness and a stiffness similar to paper used in some glass sheet packing and unpacking equipment, multilayer film 300 may be substituted for the paper without modification to the packing and unpacking equipment. By using multilayer film 300 in place of paper or other types of films, the surface quality of the glass sheets after unpacking may be improved.

[0031] FIG. 4 depicts a cross-sectional view of an exemplary stack 400 of glass sheets 404a to 404c (collectively referred to as glass sheets 404) protected by multilayer films 402a to 402d (collectively referred to as multilayer films 402). Multilayer films 402 may each be multilayer film 100, multilayer film 200, or multilayer film 300 previously described and illustrated with reference to FIGS. 1-3, respectively. Multilayer films 402 may be used to protect a single glass sheet by applying a first multilayer film 402 on the bottom surface of the glass sheet and a second multilayer film 402 on the top surface of the glass sheet.

[0032] Multilayer films 402 may also be used to protect a stack of glass sheets as illustrated by stack 400 in FIG. 4. A stack 400 of glass sheets may be protected by applying a multilayer film 402 (e.g., 402a) on the bottom surface of the glass sheet (e.g., 404a) on the bottom of the stack, a multilayer film 402 (e.g., 402b and 402c) between each of the glass sheets 404 (e.g., 404a to 404c), and a multilayer film 402 (e.g., 402d) on the top surface of the glass sheet (e.g., 404c) on the top of the stack. While three glass sheets are illustrated in stack 400, in other examples, a stack may include any suitable number of glass sheets.

[0033] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiments of the present disclosure without departing from the spirit and scope of the disclosure. Thus it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.