Articles coated with polyisobutylene-polyolefin film

Abstract

An article comprising a film attached to a paper or paperboard substrate, the film comprising polyisobutylene and a polyolefin, the film having a thickness in the range of about 3 μm to 20 μm, the article being useful for providing desirable moisture barrier and adhesion properties.

Description

[Technical Field]

[0001] This invention relates to paper or cardboard coated with a combination of polyisobutylene and polyolefin. The coating provides these substrates with water-resistant vapor properties. [Background technology]

[0002] Moisture-proof properties have traditionally been imparted to paper or cardboard by coating, usually molten polyethylene, onto a paper substrate, followed by cooling and calendering. Polyethylene has the advantages of being heat-sealable, flexible, and omniphobic. Nevertheless, despite being standard in the industry, polyethylene-coated paper and cardboard have several drawbacks. Firstly, to achieve the desired moisture-proof properties, provide adhesion to the substrate, and avoid film defects such as pinhole leaks, a thick coating of typically about 1 mil (25 microns) must be applied to the substrate. Substitutes for polyethylene, such as acrylic, do not provide acceptable moisture-proof properties. Furthermore, unlike polyethylene, acrylic is not readily heat-sealable. Polyvinylidene chloride (PVDC) is another substitute, which provides excellent moisture-proof properties with a low coat weight, but decomposes at low temperatures, causing contamination of reusable materials and causing corrosion and damage to material recycling equipment.

[0003] Therefore, in the field of paper and cardboard coatings, it would be advantageous to achieve acceptable moisture resistance with a fraction of the standard film thickness required today, not only to save raw material costs but also to make coated products suitable for recycling. Furthermore, even a reduction in the weight of the final product (e.g., paper cups), even as small as 2% by weight, has a significant impact on transportation costs. [Overview of the project]

[0004] In one aspect, the present invention addresses the needs of the art by providing an article comprising a film attached to a paper or cardboard substrate, wherein the film comprises 20 to 80 weight percent of polyisobutylene and 20 to 80 weight percent of polyolefin, and the film has a thickness in the range of about 3 μm to 20 μm.

[0005] In a second aspect, the present invention relates to a composition comprising an aqueous dispersion of a) polyisobutylene particles and b) polyolefin particles which are polyethylene particles or polypropylene particles, wherein the weight-to-weight ratio of polyisobutylene particles to polyolefin particles is in the range of 20:80 to 80:20, the composition has a solid content of 20 to 60% by weight of polyisobutylene particles and polyolefin particles, and the polyisobutylene particles and polyolefin particles are in the range of 0.1 μm to 12 μm. 90 It is a composition having particle size. [Modes for carrying out the invention]

[0006] In a first aspect, the present invention relates to an article comprising a film attached to a paper or cardboard substrate, wherein the film comprises 20 to 80 weight percent of polyisobutylene and 20 to 80 weight percent of polyolefin, and the film has a thickness in the range of about 3 μm to 20 μm.

[0007] Articles of the present invention can be prepared by coating a paper or cardboard substrate with an aqueous dispersion of polyisobutylene and polyolefin polymer particles, and then removing the water as described herein. The aqueous dispersion of polyisobutylene and polyolefin polymer particles is advantageously prepared by blending an aqueous dispersion of polyisobutylene polymer particles with an aqueous dispersion of polyolefin polymer particles. The aqueous dispersion of polyisobutylene polymer particles may also be prepared by dispersing resinous fluid polyisobutylene in water under high shear conditions in the presence of a suitable surfactant. As used herein, “polyisobutylene” refers to an isobutylene homopolymer, as well as a copolymer comprising repeating units of isobutylene and comonomers, where the isobutylene repeating units form the majority of the copolymer. Examples of copolymers include poly(isobutylene-isoprene) and poly(isobutylene-succinic anhydride). Examples of commercially available polyisobutylene (also called polyisobutene) homopolymers and copolymers include Oppanol B10, Oppanol B12, Oppanol B15, Oppanol B100, and Oppanol B200 polyisobutylene, Glissopal V190, Glissopal V500, Glissopal V640, and Glissopal V1500 polyisobutene, Vistanex LM-MH, Vistanex LM-MS, LM-H polyisobutene, Laxess X-butyl RB 100, Laxess X-butyl RB 101-3, and Laxess X-butyl RB Examples include 402 isobutylene-isoprene copolymer, as well as HRD-350, HRD-400, HRD-450, HRD-500, HRD-600, HRD-650, and HRD-950 polyisobutylene.

[0008] Suitable surfactants include alkali metals C8-C 20 -Anionic surfactants such as alkylbenzene sulfonates and sulfates, as well as secondary alcohol ethoxylates and C8-C 20-Nonionic surfactants such as alkyl glucosides are examples. Specific examples of suitable anionic surfactants include sodium dodecylbenzenesulfonate and sodium dodecylbenzenesulfate. Secondary alcohol ethoxylates are defined by the following formula: [ka] It can be characterized by the formula where x is 8 to 50, and O(CH2CH2O) x The H group is C 10~15 H 22~32 It is bonded to the CH group on the chain. Preferably, the secondary alcohol ethoxylate has the following formula [ka] It can be characterized by the formula, where x is preferably 10 to 50, and preferably 10 to 40. Examples of commercially available suitable surfactants include TERGITOL™ 15-S-40, TERGITOL 15-S-20, and TERGITOL TMN-10 secondary alcohol ethoxylate surfactant (trademark of The Dow Chemical Company or its affiliates). Suitable alkyl glucosides include decyl glucoside, dodecyl glucoside, and lauryl glucoside.

[0009] Dispersed polyisobutylene polymer particles D 90 When the particle size is determined using a dynamic light scattering particle size analyzer (e.g., Beckman LS230 Particle Size Analyzer), it ranges from 0.1 μm, preferably 0.2 μm, more preferably 0.5 μm, up to 12 μm, preferably up to 8 μm, more preferably up to 4 μm, and most preferably up to 2 μm.

[0010] Aqueous dispersions of polyolefin particles may be prepared by a continuous twin-screw extrusion process, as described in U.S. Patent Nos. 8318257 and 7803865. Dispersions of polyolefin polymer particles may be prepared by dispersing polymer particles in the presence of a dispersant, a neutralizing agent, and a coupling agent, for example, as described in U.S. Patent No. 10612913. The dispersant is preferably a copolymer (i.e., ethylene-carboxylic acid copolymer) containing structural units of ethylene and structural units of carboxylic acid monomers, the copolymer having a melt flow index in the range of 50 g / 10 min to 2000 g / 10 min, and the weight-to-weight ratio of ethylene structural units to carboxylic acid monomer structural units in the range of 95:5 to 70:30. The melt flow index range is the range determined by ASTM 1238 at a temperature of 190 °C and a load of 2.16 kg.

[0011] As used herein, suitable polyolefin particles have a broad molecular weight range but do not contain polyolefin wax, and are defined by the following formula: [ka] It may also be written as follows, where R is H or CH3, and x is in the range of 72 to 360.

[0012] The neutralizing agent may be an inorganic base or an organic base. Examples of suitable inorganic bases include ammonia, potassium hydroxide, sodium hydroxide, and calcium hydroxide, and examples of suitable organic bases include N,N-dimethylethanolamine, diethylamine, and morpholine. The concentration of the neutralizing agent is preferably high enough to neutralize at least half of the carboxylic acid groups in the dispersant. For example, if the dispersant contains 0.05 mol of carboxylic acid groups, at least 0.025 mol of a neutralizing agent such as N,N-dimethylethanolamine will be required. Thus, the ratio of the basic functional groups, preferably amine groups or ammonia, in the neutralizing agent to the carboxylic acid groups in the dispersant is preferably at least 0.5:1. The composition prepared using the dispersant and the neutralizing agent contains the neutralizing agent, or its salt, or a combination thereof.

[0013] To improve the compatibility between the dispersant and the polyolefin, a coupling agent may be included. An example of a suitable coupling agent is ethylene-co-maleic anhydride, and when this is used, it is present at a concentration in the range of 5 wt% to 20 wt%, more preferably up to 10 wt%, based on the weights of the polyolefin, the dispersant, and the coupling agent.

[0014] The D of the dispersed polyolefin particles 90 The particle size, which is also determined using a dynamic light scattering particle size analyzer, ranges from 0.1 μm, preferably from 0.2 μm, more preferably from 0.5 μm, up to 12 μm, preferably up to 8 μm, more preferably up to 4 μm, and most preferably up to 2 μm.

[0015] The polyolefin dispersion is a polypropylene dispersion or a polyethylene dispersion. As used herein, "polyethylene" refers to linear low density polyethylene, low density polyethylene, high density polyethylene, ethylene - co - octene copolymer, ethylene - co - hexene copolymer, or ethylene - alkene copolymers such as ethylene - propylene copolymer, ethylene - methyl acrylate copolymer, or ethylene - ethyl acrylate copolymer, and ethylene - carboxylic acid copolymers such as ethylene - methacrylic acid, and combinations thereof. (Ethylene - carboxylic acid copolymers are considered polyethylene when they have an acid value of less than 90 mg KOH / g.)

[0016] Examples of commercially available aqueous polyethylene dispersions include CANVERA™ 1110 polyolefin dispersion, HYPOD™ 2000 polyolefin dispersion, and RHOBARR™ 320 polyolefin elastomer dispersion (CANVERA, HYPOD, and RHOBARR are trademarks of The Dow Chemical Company or its affiliates).

[0017] As used herein, "polypropylene" refers to polypropylene homopolymers, and copolymers that contain repeating units of polypropylene and comonomers, where the polypropylene repeating units form the majority of the copolymer.

[0018] The weight - to - weight ratio of polyisobutylene polymer particles to polyolefin polymer particles, preferably polyethylene polymer particles, is preferably in the range of 25:75 to 70:30, more preferably up to 65:35.

[0019] After combining the dispersions, the composition can be applied to paper or cardboard using a wire wound draw down bar. Advantageously, the wet film is heated to a temperature in the range preferably from 50 °C, more preferably from 70 °C, preferably up to 150 °C, more preferably up to 120 °C to remove water and form a dry coating, providing a final dry film having a thickness in the range from 3 μm, preferably from 6 μm, more preferably from 8 μm, up to 20 μm, preferably up to 16 μm, more preferably up to 12 μm.

[0020] In another aspect, the invention is an article comprising a film affixed to a paper or cardboard substrate, wherein the film comprises 20 - 80 weight percent of a polyisobutylene polymer and 20 - 80 weight percent of a polyolefin which is polyethylene or polypropylene, and the film has a thickness in the range of about 4 μm - 20 μm. Preferably, the film comprises the polyisobutylene polymer and polyethylene as defined above herein. The weight - to - weight ratio of the polyisobutylene polymer to the polyolefin polymer, preferably the polyethylene polymer, in the film is preferably in the range of 25:75 to 70:30, more preferably up to 65:35.

[0021] The weight density of the paper or cardboard is in the range of 40 g / m 2 ~ 350 g / m 2 For paper, the preferred weight density is in the range of 60 g / m 2 ~ 100 g / m 2 For cardboard, the preferred weight density is in the range of 200 g / m 2 ~ 300 g / m 2 The paper or cardboard may not be coated or may be pre - coated to produce a smooth surface prior to the application of the coating formulation.

[0022] A thin coating of polyisobutylene-polyolefin film on paper or cardboard substrates has been found to impart desirable water-resistant vapor properties in combination with an acceptable low level of tackiness. The coated substrates are suitable for packaging applications where a relatively low ratio of the coating resin to the substrate weight is required for recycling purposes.

[0023] Examples Example 1 - Preparation of Polyisobutylene Resin Dispersion A (PIBD (Polyisobutylene Resin Dispersion)-A) HRD-400 polyisobutylene resin (50g, supplied by Shandong Hongrui New Material Technology Co., Inc.), TERGITOL™ TMN-10 dispersion (2.8g, 90% active ingredient), and water (2.2g) were combined and mixed for 4 minutes at 3500 rpm using a FlackTek SpeedMixer DAC 150.1 FV-K. Then, while stirring, an additional 45g of water was gradually added to a mixture with a 50% solids content and 1.13 μm D 90 A dispersion of aqueous polyisobutylene (PIB) with particle size was formed.

[0024] Example 2 - Preparation of polyisobutylene resin dispersion B (PIBD-B) HRD-400 polyisobutylene resin (50g), TERGITOL™ 15-s-9 dispersion (2.5g), and water (2.5g) were combined and mixed for 4 minutes at 3500 rpm using a FlackTek SpeedMixer DAC 150.1 FV-K. Then, while stirring, an additional 45g of water was gradually added to a mixture with a 50% solid content and 1.03 μm D 90 An aqueous PIB dispersion with particle size was formed.

[0025] Example 3 - Preparation of polyisobutylene resin dispersion C (PIBD-C) HRD-400 polyisobutylene resin (50g) and Plantacare 2000UP decyl glucoside (5g, 50% active ingredient, supplied by BASF) were combined and mixed for 4 minutes at 3500 rpm using a FlackTek SpeedMixer DAC 150.1 FV-K. Then, while stirring, additional water (45g) was gradually added to a mixture with a 50% solids content and 1.02 μm decyl glucoside particles. 90 An aqueous PIB dispersion with particle size was formed.

[0026] Example 4 - Preparation of polyisobutylene resin dispersion D (PIBD-D) HRD-400 polyisobutylene resin (50g) and DS-4 sodium dodecylbenzenesulfonate (5g, 23% active ingredient) were combined and mixed for 4 minutes at 3500 rpm using a FlackTek SpeedMixer DAC 150.1 FV-K. Then, while stirring, additional water (45g) was gradually added to a mixture with a 50% solids content and 0.87 μm D 90 An aqueous PIB dispersion with particle size was formed.

[0027] CANVERA 1110 polyolefin dispersion (CANV, 43% solids) or RHOBARR 320 polyolefin dispersion (RHOB, 43% solids) were combined with PIB dispersion at ambient temperature to form the compositions listed in Table 1. All listed amounts are grams of the total dispersion, unadjusted for solids content. [Table 1]

[0028] The coating formulation was prepared by blending the components at room temperature. This blend was then coated onto paper sheets using a wire bar with a Meyer bar automatic film coating apparatus (60 g / m²). 2 The coated film was dried at 100°C for 2 minutes, and the thickness of the dried film was controlled to 10 ± 2 μm.

[0029] Table 2 shows the water vapor transmission rate (WVTR) performance at 38°C and 90% relative humidity. WVTR was measured at 38°C and 90% relative humidity according to ASTM D3985-02 using a MOCON TRAN Model 3 / 33 Permeation Analyzer. Comparative Example 3 is a pure PIB dispersion. Film adhesion was evaluated using a PT-1000 probe adhesion tester with a probe speed of 0.5 cm / sec and a residence time of 1 second. WVTR was expressed as g / m². 2 Measured in days. WVTR reduction refers to the percentage reduction in WVTR of the coating from the PB / PE blend compared to the coating from the corresponding unblended PE dispersion in Comparative Examples 1, 2, and 4. [Table 2]

[0030] The data shows that coatings formed solely from polyethylene dispersions have insufficient WVTR (100g / m²). 2 This indicates that it is greater than 100g / m². In contrast, 100g / m² 2 WVTR of less than 1 day was achieved using coatings prepared from PIB dispersion alone or from a blend of PIB and PE dispersion. However, as shown in Table 3, a proper balance between WVTR and probe tackiness requires coatings formed from blends. Probe tackiness is measured in grams. Low tackiness is required for paper coating applications. [Table 3]

[0031] Coatings resulting from a blend of PIBD-A and CANVERA 1110 polyolefin dispersion (a high-density polyethylene dispersion) provided excellent tackiness and WVTR performance over a wide range. In contrast, coatings made from PIBD-A alone provided insufficient tackiness (above 4.5g). The present specification includes the following embodiments. Section 1. An article comprising a film attached to a paper or cardboard substrate, wherein the film comprises 20 to 80 weight percent of polyisobutylene and 20 to 80 weight percent of polyolefin, and the film has a thickness in the range of about 3 μm to 20 μm. Section 2. The article according to claim 1, wherein the polyolefin is polyethylene and the polyisobutylene is a polyisobutylene homopolymer. Section 3. The article according to claim 2, wherein the weight-to-weight ratio of the polyisobutylene homopolymer to the polyethylene is in the range of 25:75 to 70:30. Section 4. The article according to claim 2, wherein the weight-to-weight ratio of the polyisobutylene homopolymer to the polyethylene is in the range of 25:75 to 65:35. Section 5. The article according to any one of claims 1 to 4, wherein the polyethylene comprises ethylene-co-octene copolymer or ethylene-ethyl acrylate copolymer or a combination thereof. Section 6. The article according to any one of claims 1 to 4, wherein the polyethylene includes high-density polyethylene. Section 7. The article according to item 1, further comprising a dispersant and a coupling agent.

Claims

1. An article comprising a dry coating film attached to a paper or cardboard substrate, wherein the dry coating film is derived from an aqueous dispersion of polyisobutylene homopolymer particles and polyethylene particles, comprising 20 to 80 weight percent of polyisobutylene homopolymer and 20 to 80 weight percent of polyethylene, and the dry coating film having a thickness in the range of about 3 μm to 20 μm.

2. The article according to claim 1, wherein the weight-to-weight ratio of the polyisobutylene homopolymer to the polyethylene is in the range of 25:75 to 70:

30.

3. The article according to claim 1, wherein the weight-to-weight ratio of the polyisobutylene homopolymer to the polyethylene is in the range of 25:75 to 65:

35.

4. The article according to any one of claims 1 to 3, wherein the polyethylene comprises ethylene-co-octene copolymer or ethylene-ethyl acrylate copolymer or a combination thereof.

5. The article according to any one of claims 1 to 3, wherein the polyethylene includes high-density polyethylene.

6. The article according to claim 1, further comprising a dispersant and a coupling agent.

Images