WO2012038976A2

WO2012038976A2 - Biocompostable paper polymer laminate and a method for preparation thereof

Info

Publication number: WO2012038976A2
Application number: PCT/IN2011/000651
Authority: WO
Inventors: Champat Rikhabchand Sanghvi; Deepak Champat Sanghvi
Original assignee: Champat Rikhabchand Sanghvi; Deepak Champat Sanghvi
Priority date: 2010-09-22
Filing date: 2011-09-21
Publication date: 2012-03-29
Also published as: WO2012038976A3

Abstract

The present invention relates to biocompostable paper polymer laminate comprises of a paper, a biocompostable polymeric film and an adhesive, wherein the said laminate is produced by application of the adhesive on the said biocompostable polymeric film, which is then exposed to heat under oven chamber at temperature about 60 to 100°C for adhesion which is followed by application of the said paper to the said biocompostable polymeric film and laminated in pinch roller. Thus produced laminate is called 2-ply laminate, which is collected on the take-up roll. In order to prepare 3-ply paper polymeric film laminate, the said 2-ply laminate is again passed through the above mentioned process, wherein the said biocompostable polymeric film is applied on the other side of the paper.

Description

BIOCOMPOSTABLE PAPER POLYMER LAMINATE AND A METHOD FOR PREPARATION THEREOF

FIELD OF INVENTION

The present invention relates to a biocompostable paper polymer laminate and a method for preparation thereof. In particular, the present invention relates to paper polymer laminate which is completely biocompostable and the preparation method for the same.

BACKGROUND OF INVENTION

Lamination is a process of applying a film to either one side or both the sides of a paper document. Laminate is called 2 -ply, when the film is applied on one side of the paper, whereas 3 -ply laminate is when the film is applied on both the sides of the paper. Materials used therein for lamination are variable. The said laminates are secured to the base with adhesives.

Lamination is done for various purposes. Lamination is basically used to protect the important documents from adverse environmental conditions like moisture, tear and tampering. Thus it gives the encased documents a longer shelf life. The use of lamination is now not restricted to paper lamination only. The scope of lamination is now hereby extended to many other uses. Lamination, through the present invention, can be used for enclosable envelops, carry bags with side seal, carry bags with various handle options, courier envelope, packaging material for dry as well as semi wet food packaging as well as industrial packaging. Lamination further adds luster to the documents.

There are various types of paper that can be used for lamination like decor paper, overlay paper, laminating Kraft, absorbent Kraft, etc. The decor paper can be used to give visual appearance to the laminate. The impregnated resin and cellulose used have about the same refraction index. Thus the cellulose fibers of the paper appear just as a shade such that only the dye stuff and pigments are visible. The overlay papers are made up from pure cellulose, made up of well delignified pulp. The paper becomes transparent on impregnation, such that the decor of the paper is seen through. The absorbent Kraft paper used is a normal paper with controlled absorbency. The characteristics of the said paper can be tailored, similarly to regular paper, by conventional processes well known to those skilled in the art of paper making. Kraft paper is preferably used for lamination. Further the paper selected for lamination process has to be compatible with the polymeric film and the laminating process. The said paper must also permit writing or printing to be placed there on using conventional writing implements, printing equipments and/ or inks. Moreover, suitable ink for printing the image limited to solvent or water based inks. For such general paper activities, the desirable opacity is at least about 72%. Higher value of opacity helps in such activities.

Popularly, polymeric film/ sheet used for lamination is composed of thermoplastic material or biodegradable material but these are not completely biocompostable. Moreover the films prepared from the said thermoplastic material are noncompostable and they may also transmit the printing ink inside the container. Usually the films prepared from the said biodegradable material are not completely biocompostable due to the presence of the heavy metal particles. Most of the available laminates do not meet the standards established by AIB- VINCOTTE, in their verification test Standards and specifications for polymeric film to be used as compostable film. Ideal lamination must comply with the compostability norms such as EN 13432, ASTM D6400 and ISO 17088 to be used as compostable product. Most of available films do not even test for the compostability. And also the material used to prepare the polymeric film has to be selected according to its ability to be adhered to the paper. Further the adhesives usually used in the available laminates to adhere the said polymeric film to the paper are silicon based adhesive which are noncompo stable. Moreover, the films usually used for lamination do not provide required tear resistance and durability.

PRIOR ART OF INVENTION

Various types of laminations are produced and patented, but they have several disadvantages as compared to the proposed invention as described below:

The Patent Application WO2010045201 wherein "PAPER/ BIODEGRADABLE PLASTIC LAMINATE AND ELECTROMAGNETIC SHIELDING MATERIAL" includes a paper web laminated to a biodegradable polymeric film using 100% solids, or solvent-less adhesives. Also the electromagnetic shielding material, as patented, includes the conducting layer interposed between the receiving antenna and a transmitting antenna, which is used to prevent the reading of the chip inserted within. But the said invention is not for the lamination of the paper, which is completely biocompo stable.

The US Patent Application 2010062269 wherein "LAMINATED PAPER PACKAGING MATERIAL AND METHOD OF PRODUCING THE SAME" comprises of a paper as the core layer, a barrier layer and a thermoplastic resin layer. But, in the said invention, the oxygen permeability is required to be checked with oxygen permeably measuring apparatus, the parameters of which needs to be changed on the basis of humidity. The packaging can be used only for s of liquid food and the like.

The Patent No. GB 2455599 wherein "A COMPOSITE/ BIODEGRADABLE PLASTIC AND PAPER LAMINATE PACKAGING BAG" comprises a single or a plurality of layers of paper is used and biodegradable plastic is used for the lining of the inner wall of the cavity of the bag used for carrying the contents of the retail pack. The respective layers are laminated together by biodegradable adhesive applied at spaced locations. But, the said invention is for the retain packaging of ready to eat food products only, which are sealed at the top after filing the bag. They are not reusable and needs to be discarded once they are opened.

The Patent No. US 7393592 wherein "Lamination grade coextruded heat-sealable film" includes a core layer of a thermoplastic polymer having a first side and a second side. A functional layer which is printable, sealable, or can be laminated or is treatable for printing, sealing, or laminating is on the first side of the core layer. A heat-sealable layer is on the second side of the core layer. The heat-sealable layer is composed of a thermoplastic polymer and an amount of a slip system, based upon the entire weight of the heat-sealable layer, sufficient to reduce the coefficient of friction and improve the slip performance of the film structure. The slip system is composed of a silicone gum and at least one antiblocking agent. The film structure exhibits the desirable combination of improved converting performance and excellent machinability performance. But the said invention is composed of thermoplastic polymer which is not biocompostable. Moreover, the said thermoplastic polymer transmits the printing ink inside the container. Also the adhesive used in the said patent is a silicone based adhesive which is noncompostable due to presence of the metals.

DISADVANTAGES OF PRIOR ART

The above mentioned inventions suffer from at least one of the following problems: i. Most of them claim for biodegradable film for lamination, which are not completely compostable due to the presence of the heavy metal particles. ii. Many of them claim for thermoplastic polymeric films which are not compostable. iii. Some of them use silicon based adhesives for adhering film to paper which are non compostable. iv. Some of them transmit Printing ink inside the container due to the use of thermoplastic polymeric material. v. Many of them do not even test for compostability.

Thus, there was a need for biocompostable paper polymer laminate which is completely biocompostable, durable and reusable.

OBJECTS OF INVENTION

The main object of the present invention is to provide biocompostable paper polymer laminate which is completely biocompostable. Another object of the present invention is to provide biocompostable polymeric film which does not contain heavy metal particles. Yet another object of the present invention is to provide a biocompostable paper polymer laminate which starts composting in presence of soil bacterial even without composting conditions.

Yet another object of the present invention is to provide a biocompostable paper polymer laminate which it does not transmit the printing ink inside the container as it uses biocompostable polymeric film.

Further object of the present invention is to provide a biocompostable paper polymer laminate which uses the wax based adhesive which is completely biocompostable.

DETAIL DESCRIPTION OF INVENTION The present invention relates to a biocompostable paper polymer laminate which is completely biocompostable.

The biocompostable paper polymer laminate characterized in which the said laminate comprises of:

· A paper;

• A biocompostable polymeric film and

• An adhesive.

The paper characterized in the said laminate can be laminated on either one side or both the sides of the paper whereby the thickness of the said paper ranges from 32 to 50 GSM, preferably 42 to 45 GSM. The said paper used in the present invention is of a biocompostable type. The said paper is preferably Kraft paper. Further the said paper has a surface that permits writing or printing.

Moreover the said paper has Tensile strength in range of 2 to 7 kN/m, Tear strength in range of 380 to 770 mN, Burst strength in range of 200 to 340 kPa, opacity in range of 72% to 79%.

Moreover the paper of the present invention is tested as per certain standards and the test data are as mentioned below:

TABLE 1

PAPER SPECIFICATIONS

The biocompo stable polymeric film characterized in the said laminate is composed of biocompostable polymeric material. The said biocompo stable polymeric film is applied on either one or both the sides to the said paper with the adhesive, whereby the thickness of the said biocompostable polymeric films ranges from 10 to 50 microns, preferably 12 microns. Further the said biocompostable polymeric film of the present invention is produced by blending the biocompostable polymers with biocompostable slip and anti blocking agent and co-extruding the said blend on blow film extruder. The said biocompostable polymers are starch based material and the said biocompostable slip is preferably 0.05 to 0.2% erucamide ESA and antiblocking agent is preferably 0.5 to 0.7% fine talcum.

The adhesive characterized in the said laminate is selected from the wax based adhesive such as solvent- based adhesives, water- based adhesives, hot- melt adhesives, ultraviolet radiation based adhesives, beam- curable adhesives or a combination thereof. Preferably, curable urethane is used as adhesive. Moreover, the thickness of the said adhesive ranges from 2 to 5 GSM.

The paper polymer laminate is produced by below mentioned process:

I. Application of the adhesive on the said biocompostable polymeric film;

II. Exposure to heat under oven chamber at temperature about 60 to 100°C for adhesion;

III. Application of the said paper to the said biocompostable polymeric film;

IV. Lamination of the paper to the biocompostable polymeric film by pinch roller;

V. Collection of 2 -ply laminate on the take-up roll and

VI. Repeating the steps I to V in order to prepare 3 -ply laminate by adhering the biocompostable polymeric film to other side of paper with the adhesive.

As characterized in the above mentioned process a thin coat of adhesive is generated on calendar roll is then transferred to the kiss roll station and the biocompostable polymeric film is also passed through the kiss roll station to deposit the said adhesive onto one side of the said biocompostable polymeric film. After the application of the adhesive, the said biocompostable polymeric film is made to pass through an oven chamber station for exposure to a temperature of about 60 to 100°C so as to adhere the said adhesive to the said biocompostable polymeric film for a time sufficient to initiate curing. The paper is then applied to the adhesive side of the said biocompostable polymeric film and passed through the pinch roller to laminate the said the biocompostable polymeric film to the said paper and thus produced laminate is then collected on take up roll. The said laminate is 2-ply biocompostable paper polymer laminate.

In order to prepare 3 -ply paper polymeric film laminate, the said 2-ply biocompostable paper plastic laminate is again passed through the steps I to IV, wherein the said biocompostable polymeric film is applied on the other side of the paper. Further, lamination process may be repeated upon the requirement of the strength of the laminate.

The laminate thus produced, as a combination of the paper and the biocompostable polymeric film along with the adhesive, is completely biocompostable and dimensionally stable in nature. Further the said laminate gets composted within 180days from the day it arrives in compost site and even without composting condition in presence of soil bacterial. After a short period of time depending on the composting site, the product is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass.

Moreover the 3-ply paper polymeric film laminate has Tensile strength in range of 230 to 440 kgf/cm², Oxygen transmission rate is 69.86 ml/m²/day, Heat Seal Strength is 6.21 kgf/ 15mm width, Bond strength is 209.5 gf/ 15mm width, Elongation in range of 2.70 to 3.60 %. Moreover the 3-ply paper polymeric film laminate of the present laminate is tested by INDIAN INSTITUTE OF PACKAGING as per the standards mentioned below: TABLE 2

Biocompostable Polymeric Film Specifications

The polymeric film of the present invention complies, the standards established by AIB- VINCOTTE, in their verification test Standards and specifications for polymeric film to be used as compostable film by fulfilling the criteria for the compostability norms which are as below:

1) AVI test program with reference OK 1 edition D,

2) EN 13432 (09-2000) - Requirements for packaging recoverable through composting and biodegradation,

3) ASTM D 6400-04 - Standard specification for compostable plastics, 4) ISO 17088 (03-2008) - specification for compostable plastics. EXAMPLE: A thin coat of curable two- component urethane laminating adhesive is generated on a calendar roll, which is then transferred to a kiss roll station. 2 rolls of 60 gauge biocompostable polymeric film is then passed through the kiss roll station to deposit the said adhesive onto one side of the said film. The said film with the adhesive is then exposed to a temperature of about 60 to 100°C in an oven chamber. The said film is then passed through a pinch roller with the paper of 30 GSM and a 2-ply paper plastic laminate is produced. The 2-ply paper plastic laminate is collected on a take-up roll. The said 2-ply paper plastic laminate is then passed through the kiss roll station to apply adhesive to the second side of the film, and the said 2-ply paper plastic laminate is then passed through an over at temperature about 60 to 100°C, which is then shifted to pinch roller and the second layer of the said film is adhered to second surface of the said paper and 3 -ply laminate is produced and 5kg paper plastic laminate is collected on take up roll.

Claims

1. A biocompostable paper polymer laminate characterized in which the said laminate comprises of:

o A paper;

o A biocompostable polymeric film and

o Adhesive.

2. A biocompostable paper polymer laminate as claimed in claim 1, wherein the thickness of the paper is in range of 32 to 50 GSM.

3. A biocompostable paper polymer laminate as claimed in claim 1, wherein the tensile strength of the paper is in range of 2 to 7 kN/m.

4. A biocompostable paper polymer laminate as claimed in claim 1, wherein the tear strength of the paper is in range of 380 to 770 mN.

5. A biocompostable paper polymer laminate as claimed in claim 1, wherein the opacity of paper is in the range of 72 to 79%.

6. A biocompostable paper polymer laminate as claimed in claim 1, wherein the burst strength of the paper is in range 200 to 340 kPa.

7. A biocompostable paper polymer laminate as claimed in claim 1, wherein the paper is preferably Kraft paper.

8. A biocompostable paper polymer laminate as claimed in claim 1, wherein the biocompostable polymeric film comprises of biocompostable polymers, biocompostable slip and anti blocking agent.

9. A biocompostable paper polymer laminate as claimed in claims 1 and 8, wherein the biocompostable polymers are starch based material.

10. A biocompostable paper polymer laminate as claimed in claims 1 and 8, wherein the biocompostable slip is preferably erucamide ESA.

11. A biocompostable paper polymer laminate as claimed in claims 1, 8 and 10, wherein the biocompostable slip is in range of 0.05 to 0.2%.

12. A biocompostable paper polymer laminate as claimed in claims 1 and 8, wherein the antiblocking agent is preferably fine talcum.

13. A biocompostable paper polymer laminate as claimed in claims 1, 8 and 12, wherein the antiblocking agent is in range of 0.5 to 0.7%.

14. A biocompostable paper polymer laminate as claimed in claim 1, wherein the thickness of biocompostable polymer film is in range of 10 to 50 microns, preferably 12 microns.

15. A biocompostable paper polymer laminate as claimed in claim 1, wherein the adhesive is wax based which is selected from solid adhesives or solvent- based adhesive or water- based adhesives or hot- melt adhesives or ultraviolet radiation based adhesives or beam- curable adhesives or a combination thereof.

16. A biocompostable paper polymer laminate as claimed in claim 1 and 15, wherein the adhesive is preferable curable urethane.

17. A biocompostable paper polymer laminate as claimed in claim 1, 15 and 16, wherein the thickness of the adhesive ranges from 2 to 5

GSM. 12/038976

18. A biocompostable paper polymer laminate as claimed in claim 1, wherein the said laminate is produced by below mentioned process:

I. Application of the adhesive on the said biocompostable polymeric film;

III. Application of the said paper to the said biocompostable polymeric film;

V. Collection of 2-ply laminate on the take-up roll and

VI. Repeating the steps I to IV in order to prepare 3-ply laminate by adhering the biocompostable polymeric film to other side of paper with the adhesive.

19. A biocompostable paper polymer laminate as claimed in claims 1 and 18, wherein the tensile strength of the 3-ply laminate is in range of 230 to 440 kgf/cm².

20. A biocompostable paper polymer laminate as claimed in claims 1 and 18, wherein the heat Seal Strength of the 3-ply laminate is 6.21 kgf/ 15mm width.

A biocompostable paper polymer laminate as claimed in claims 1 and 18, wherein bond strength of the 3-ply laminate is 209.5 gf/ 15mm width.