Composite paper and preparation method thereof

Abstract

A composite paper comprising: a paper substrate having a top surface and a bottom surface; and a coating on at least a portion of the top surface of the paper substrate; wherein the coating layer is formed from a composition comprising a cellulose ester resin and at least one organic solvent; wherein the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to composite papers and methods of making the same, and more particularly to composite papers having improved light transmittance. Background Art

[0002] Paperboard is widely used in packaging applications. For example, folding cartons are extremely popular in secondary packaging for cosmetics, jewelry, and other luxury consumer goods (such as wine). In addition to conventional packaging, high-end packaging also emphasizes the need to communicate brand value and quality to consumers, thereby increasing brand awareness and consumer loyalty. It may be very desirable that at least one side of the folding carton is transparent, thereby allowing consumers to see and experience the design of the primary container without opening the box. In order to achieve the desired effect, conventional packaging (such as gift boxes) usually includes a window made of plastic film. Plastic windows are usually transparent, allowing consumers to observe the primary packaging without opening the box. However, due to the introduction of plastic windows, the paper industry believes that the box itself is not recyclable. In addition, the introduction of plastic windows also makes the box more difficult to be compostable or biodegradable. Therefore, there is a need for a carton that is recyclable according to paper industry standards and potentially compostable or biodegradable while allowing consumers to experience the design of the primary packaging.

[0003] Thus, there remains a need for composite papers for packaging of high-end consumer products, such as secondary packaging for cosmetics and jewelry, that provide improved light transmittance and clarity while enabling recycling, composting, and biodegradation of the packaging. Summary of the Invention

[0004] Embodiments herein disclose composite paper. The composite paper comprises a paper substrate having a top surface and a bottom surface; and a coating on at least a portion of the top surface of the paper substrate; wherein the coating is formed from a composition comprising: a cellulose ester resin and at least one organic solvent; wherein the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035.

[0005] Embodiments herein also disclose a method for making a composite paper. The method comprises: providing a paper substrate having a top surface and a bottom surface; coating at least a portion of the top surface of the paper substrate with a composition, wherein the composition comprises a cellulose ester resin and at least one organic solvent; and drying the composition to form a coating; wherein a composite paper is formed in which the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035.

[0006] Embodiments herein further disclose a method for making a composite paper. The method comprises: providing a paper substrate having a top surface and a bottom surface; providing a coating, wherein the coating is formed from a composition comprising: a cellulose ester resin and at least one organic solvent; and laminating at least a portion of the top surface of the paper substrate with the coating to form the composite paper; wherein the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035.

[0007] Embodiments herein further disclose articles made from composite paper. The article comprises composite paper, wherein the composite paper comprises a paper substrate having a top surface and a bottom surface; and a coating on at least a portion of the top surface of the paper substrate; wherein the coating is formed from a composition comprising: a cellulose ester resin and at least one organic solvent; wherein the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035. In one or more embodiments herein, the article is recyclable, compostable, or biodegradable. Recyclability, compostability, or biodegradability can be determined according to standards set by the papermaking industry.

[0008] Additional features and advantages of the embodiments will be described in the detailed description that follows, and some features and advantages will become apparent to those skilled in the art from that description or by practicing the embodiments described herein. It should be understood that the foregoing and following descriptions describe various embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. DETAILED DESCRIPTION

[0009] Reference will now be made in detail to embodiments of composite papers and methods of making the same. The composite papers described herein may be used in the packaging of high-end consumer products, such as cosmetics and jewelry. However, it should be noted that this is merely an illustrative implementation of the embodiments disclosed herein. The embodiments are applicable to other technologies that are susceptible to issues similar to those discussed above. For example, the composite papers described herein may be used in other packaging applications, such as for food, pharmaceuticals, or electronics; or in the preparation of articles, such as signs, labels, signs, or posters, all of which are within the scope of embodiments of the present invention.

[0010] In embodiments herein, composite paper comprises a paper substrate and a coating on at least a portion of the top surface of the paper substrate. The paper substrate has a top surface and a bottom surface and can be tracing paper, writing paper, security paper, text paper, cover paper, kraft paper, security paper, or cardboard. As used herein, tracing paper can include glassine, vellum, impregnated paper, and parchment or any paper substrate with transparent or translucent properties. The paper described herein can be obtained by forming a fibrous substrate into a thin planar element with pulp fibers. In some embodiments, the paper substrate is selected from tracing paper, writing paper, security paper, text paper, cover paper, kraft paper, security paper, or cardboard.

[0011] In one or more embodiments described herein, the paper substrate has a refractive index of at least 1.40. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the paper substrate has a refractive index ranging from a lower value of 1.40, 1.42, 1.45, or 1.47 to an upper value of 1.65, 1.60, 1.55, 1.50, or 1.48. In other embodiments, the paper substrate has a refractive index of 1.42 to 1.60, 1.45 to 1.55, or 1.45 to 1.50.

[0012] The coating is formed from a composition comprising a cellulose ester resin and at least one organic solvent. The composition may comprise from 1 to 40 wt.% of the cellulose ester resin and from 60 to 99 wt.% of the at least one organic solvent. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the composition may comprise from a lower limit of 1, 3, or 5 wt.% to an upper limit of 40, 37, 35, 30, or 25 wt.% of the cellulose ester resin and from a lower limit of 60, 63, 65, 70, or 75 wt.% to an upper limit of 99, 97, or 95 wt.% of the at least one organic solvent.

[0013] In one or more embodiments herein, the cellulose ester resin may be selected from cellulose acetate resin, cellulose acetate butyrate resin, cellulose acetate propionate resin, and combinations thereof. In one or more embodiments herein, the cellulose ester resin may be selected from cellulose acetate butyrate resin, cellulose acetate propionate resin, and combinations thereof.

[0014] In one or more embodiments herein, the cellulose ester resin may have a falling ball viscosity of less than 3.0 seconds as measured according to ASTM D1343. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the cellulose ester resin may have a falling ball viscosity of less than 2.75, 2.5, 2.0, or 1.5 seconds. In other embodiments, the cellulose ester resin may have a falling ball viscosity of less than 0.2, 0.5, or 1.0 seconds to less than 3.0, 2.5, or 2.0 seconds as measured according to ASTM D1343.

[0015] In one or more embodiments herein, the cellulose ester resin may have a refractive index of at least 1.40. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the cellulose ester resin has a refractive index ranging from a lower value of 1.40, 1.42, 1.45, or 1.47 to an upper value of 1.65, 1.60, 1.55, 1.50, or 1.48. In other embodiments, the cellulose ester resin has a refractive index of 1.42 to 1.60, 1.45 to 1.55, or 1.45 to 1.50.

[0016] In one or more embodiments herein, the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.035. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.030, less than 0.0275, or less than 0.025.

[0017] In one or more embodiments of this invention, at least one organic solvent is selected from ester, alcohol, ketone, glycol ether, glycol ether ester, hydrocarbon and combination thereof.Exemplary ester organic solvent can include but is not limited to ethyl acetate (2-EH acetate), decyl acetate, diethyl carbonate, dimethyl carbonate, EG acetate, ethyl lactate, heptyl acetate, hexyl acetate, isobutyl acetate, isobutyl isobutyrate, isopropyl acetate, methyl acetate, n-butyl propionate, n-pentyl propionate, ethyl acetate, n-propyl acetate, octyl acetate, p-pentyl acetate, propylene carbonate, sec-butyl acetate, tert-butyl acetate, n-butyl acetate or combination thereof.Exemplary alcohol can include but is not limited to 2-ethylhexanol, amyl alcohol, benzyl alcohol, cyclohexanol, diacetone alcohol, diisobutyl carbinol, ethanol, furfuryl alcohol, hexanol, isobutyl alcohol, isopropyl alcohol, methanol, methyl amyl carbinol, methyl isobutyl carbinol, n-butanol, n-propyl alcohol, sec-butyl alcohol, the tert-butyl alcohol or combination thereof. Exemplary ketones may include, but are not limited to, methyl ethyl ketone, acetone, butyrolactone, cyclohexanone, cyclopentanone, diisobutyl ketone, isophorone, mesityl oxide, methyl amyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl propyl ketone, n-butylpyrrolidone, n-ethylpyrrolidone, n-methyl-2-pyrrolidone, or combinations thereof. Exemplary glycol ethers may include, but are not limited to, 1,2-dimethoxyethane, ethylene glycol phenyl ether, propylene glycol phenyl ether, dipropylene glycol methyl ether, dipropylene glycol n-butyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether acetate, ethylene glycol 2-ethylhexyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol hexyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, propylene glycol tert-butyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, propylene glycol monomethyl ether, or a combination thereof. Exemplary glycol ether esters may include, but are not limited to, propylene glycol methyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl acetate, ethylene glycol monobutyl ether acetate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, or a combination thereof. Exemplary hydrocarbons may include, but are not limited to, cyclohexane, n-heptane, n-hexane, n-octane, ethylbenzene, toluene, xylene, or combinations thereof.

[0018] In one or more embodiments herein, at least one organic solvent is an organic solvent mixture of a first organic solvent having a boiling point temperature greater than or equal to 90°C and a second organic solvent having a boiling point temperature less than 90°C. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, at least one organic solvent is an organic solvent mixture of a first organic solvent and a second organic solvent, the boiling point temperature of the first organic solvent being in the range of a lower limit of 90°C, 95°C, 100°C or 105°C to an upper limit of 150°C, 145°C, 140°C, 135°C or 130°C, and the boiling point temperature of the second organic solvent being in the range of a lower limit of 40°C, 50°C, 55°C or 60°C to an upper limit of less than 90°C, 87°C or 85°C. The boiling point can be measured according to the Thiele tube method commonly used and familiar to those skilled in the art.

[0019] In one or more embodiments herein, the organic solvent mixture comprises at least 5 wt.% of the first organic solvent. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the organic solvent mixture can comprise a lower limit of 5, 7.5, or 10 wt.% to an upper limit of 60, 55, 50, 45, or 40 wt.% of the first organic solvent. In other embodiments, the organic solvent mixture can comprise 5 wt.% to 60 wt.% or 5 wt.% to 50 wt.% of the first organic solvent.

[0020] In one or more embodiments herein, the composition may further comprise a thermoplastic acrylic resin. Examples of thermoplastic acrylic resins may include, but are not limited to, alkyl (meth) acrylic resins, alkyl (meth) acrylate resins, styrene (meth) acrylic resins, styrene (meth) acrylate resins, vinyl acetate (meth) acrylic resins, vinyl acetate (meth) acrylate resins, or mixtures thereof. Exemplary commercially available thermoplastic acrylic resins include, but are not limited to, NEOCRYL TM B-814, NEOCRYL TM B-805, NEOCRYL M B-817, DEGALAN TM N 742N、DIANAL TM BR-106, etc. In one or more embodiments herein, the composition may include up to 25 wt.% of a thermoplastic acrylic resin. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the composition may include a thermoplastic acrylic resin with a lower limit of 0, 1, 5, 7, or 10 wt.% and an upper limit of 25, 20, or 15 wt.%.

[0021] In one or more embodiments herein, the composite paper may exhibit one or more of the following properties: a haze value of less than 90% as measured according to ASTM D1003; a total transmittance value of at least 80% as measured according to ASTM D1003; and / or a transmittance of collimated and narrow angle light value greater than 4% as measured according to ASTM D1003. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the composite paper may exhibit one or more of the following properties: a haze value of 20%, 30%, or 40% as measured according to ASTM D1003, ranging from a lower limit of 90%, 87.5%, or 85% to an upper limit of 80%, 87.5%, or 85% to a total transmittance value of 80% as measured according to ASTM D1003, ranging from a lower limit of 95% to an upper limit of 80%, and / or a transmittance of collimated and narrow angle light value of greater than 4% as measured according to ASTM D1003, ranging from a lower limit of 85%, 75%, 50%, or 35%.

[0022] The embodiments described herein also disclose methods for making composite paper as previously described herein. In some embodiments, the method comprises providing a paper substrate having a top surface and a bottom surface; coating at least a portion of the top surface of the paper substrate with a composition; and drying the composition to form a coating; wherein a composite paper is thereby formed. In other embodiments, the method comprises providing a paper substrate having a top surface and a bottom surface; providing a coating; and laminating at least a portion of the top surface of the paper substrate with the coating to form a composite paper. The coating can be formed using conventional coating techniques, including continuous coating and dip coating procedures. The composition can be applied to have a dry coating thickness of about 0.5 to about 8 microns. The coating can be dried at a temperature of about 20°C to about 200°C. While an ambient temperature of 20°C may require several hours of drying time, elevated temperatures (e.g., 150°C) will dry the coating in less than a few minutes. If desired, the coating can be subjected to a chemical or physical surface modification treatment to improve the bond between the coating and the paper substrate.

[0023] Test Method

[0024] Refractive index

[0025] Refractive index is measured according to ASTM D542 at room temperature (about 20°C) on film or paper samples approximately 1" x 1" in size and 30-50 mils thick.

[0026] Light transmittance

[0027] The light transmittance of paper substrates and paper composites is measured according to ASTM D1003. t It consists of light that is transmitted but scattered at an angle greater than 2.5 degrees relative to the incident light (diffuse light transmittance (T d )), light transmitted parallel to the incident light (T P) and light that is transmitted but scattered within 2.5 degrees relative to the incident light (T N ). The haze of the sample is defined as T d With T t The ratio is the percentage of light that, on average, passes through the sample and deviates from the incident beam by more than 2.5 degrees.

[0028] Example

[0029] The following specific examples are given to illustrate performance characteristics associated with paper composites.

[0030] Table 1 - Raw materials

[0031]

[0032]

[0033] Table 2 - Refractive Index of Cellulose Ester Resins and Tracing Paper

[0034] Refractive index CAP482-0.5 1.475 CAP504-0.2 1.455 <![CDATA[ENSURE TM 100]]> 1.475 Tracing paper 70 1.45～1.50 Tracing paper 90 1.45～1.50

[0035] Table 3 - Boiling Temperatures of Solvents*

[0036] Boiling point, °C Ethyl acetate 77.1 n-propyl acetate 102.0 Butyl acetate 126.0 Isopropyl alcohol 82.5 Methyl ether ketone 79.6 Propylene glycol monomethyl ether 120.0

[0037] *Information provided on the technical data sheet.

[0038] An exemplary formulation was prepared as follows:

[0039] Invention Example 1

[0040] 5 grams of CAP 504-0.2 was dissolved in a mixture of 85.5 grams of methyl ether ketone and 9.5 grams of butyl acetate in a glass container. A 4-inch x 4-inch sample of Tracing Paper 70 was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0041] Invention Example 2

[0042] 5g ENSURE TM 100 was dissolved in a mixture of 30.0 g of ethyl acetate, 22.0 g of propyl acetate, 11.5 g of isopropyl alcohol, 20.0 g of methyl ether ketone, and 11.5 g of butyl acetate in a glass container. A 4-inch x 4-inch piece of tracing paper 70 was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0043] Invention Example 3

[0044] 5 grams of CAP 504-0.2 were dissolved in a mixture of 85.5 grams of methyl ether ketone and 9.5 grams of butyl acetate in glass container No. 1, and 15 grams of CAP 504-0.2 were dissolved in a mixture of 72.25 grams of methyl ether ketone and 12.75 grams of butyl acetate in glass container No. 2. A 4-inch x 4-inch piece of tracing paper 70 was then immersed in the solution in container No. 1 for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was immersed in container No. 2 for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0045] Invention Example 4

[0046] 5g ENSURE TM 100 was dissolved in a mixture of 30.0 g of ethyl acetate, 22.0 g of propyl acetate, 11.5 g of isopropyl alcohol, 20.0 g of methyl ether ketone and 11.5 g of butyl acetate in a No. 1 glass container. TM 100 was dissolved in a mixture of 25.0 grams of ethyl acetate, 19.0 grams of propyl acetate, 9.5 grams of isopropyl alcohol, 17.0 grams of methyl ether ketone, and 9.5 grams of butyl acetate in glass container No. 2. A 4-inch x 4-inch piece of tracing paper 70 was then immersed in the solution in container No. 1 for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was immersed in the solution in container No. 2 for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0047] Invention Example 5

[0048] 15 grams of CAP 504-0.2 was dissolved in a mixture of 20.0 grams of ethyl acetate, 15.0 grams of propyl acetate, 15.0 grams of isopropyl alcohol, 25.0 grams of methyl ether ketone, and 10.0 grams of propylene glycol monomethyl ether in a glass container. A 4-inch x 4-inch piece of tracing paper 70 was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was immersed in the solution again for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0049] Comparative Example 1

[0050] The light transmittance of 4 inch x 4 inch tracing paper 70 was evaluated. The results are listed in Table 4.

[0051] Invention Example 6

[0052] 15 grams of CAP 482-0.5 was dissolved in a mixture of 19.0 grams of ethyl acetate, 33.0 grams of propyl acetate, 4.0 grams of isopropyl alcohol, 23.0 grams of methyl ether ketone, and 6.0 grams of butyl acetate in a glass container. A 4-inch x 4-inch piece of tracing paper 90 was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was again immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0053] Invention Example 7

[0054] 20g ENSURE TM 100 was dissolved in a mixture of 25.0 grams of ethyl acetate, 19.0 grams of propyl acetate, 9.5 grams of isopropyl alcohol, 17.0 grams of methyl ether ketone, and 9.5 grams of butyl acetate in a glass container. A 4-inch x 4-inch piece of tracing paper 90 was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was again immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0055] Comparative Example 2

[0056] The light transmittance of 4 inch x 4 inch tracing paper 90 was evaluated. The results are listed in Table 4.

[0057] Inventive Example 8

[0058] 15 grams of CAP 504-0.2 was dissolved in a mixture of 20.0 grams of ethyl acetate, 15.0 grams of propyl acetate, 15.0 grams of isopropyl alcohol, 25.0 grams of methyl ether ketone, and 10.0 grams of propylene glycol monomethyl ether in a glass container. A 4-inch x 4-inch piece of copy paper was then immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, the paper was again immersed in the solution for 30 seconds, removed from the solution, and allowed to dry at room temperature for approximately 60 seconds. After further drying in an oven set at 90°C for approximately 90 seconds, a composite paper coated on both sides was obtained. The light transmittance of the composite paper was evaluated. The results are listed in Table 4.

[0059] Comparative Example 3

[0060] The light transmittance of 4 inch x 4 inch copy paper was evaluated. The results are shown in Table 4.

[0061] Table 4 - Results

[0062]

[0063] As shown in the table above, the formulations of the present invention exhibit lower haze, increased total light transmittance, and higher transmission of parallel and narrow angle light compared to paper alone.

[0064] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "approximately 40 mm."

[0065] Each document cited herein, if any (including any cross-referenced or related patents or applications and any patent applications or patents from which this application claims priority or the benefit of) is hereby incorporated by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document does not admit that it is prior art with respect to any invention disclosed or claimed herein, nor does it admit that it, alone or in combination with any other reference or references, teaches, suggests, or discloses any such invention. In addition, if any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall prevail.

[0066] While particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended that all such changes and modifications that are within the scope of the invention be covered in the appended claims.

Claims

1. A composite paper, comprising: a paper substrate having a top surface and a bottom surface; and a coating on at least a portion of the top surface of the paper substrate; wherein the coating is formed from a composition comprising: cellulose ester resin, and at least one organic solvent; wherein the difference between the refractive index of the paper substrate and the refractive index of the at least one cellulose ester resin is less than 0.

035.

2. The composite paper of claim 1, wherein the cellulose ester resin has a falling ball viscosity of less than 2.0 seconds as measured according to ASTM D1343.

3. The composite paper according to claim 1 or 2, wherein the cellulose ester resin is selected from the group consisting of cellulose acetate resin, cellulose acetate butyrate resin, cellulose acetate propionate resin, and combinations thereof.

4. The composite paper of claims 1-3, wherein the at least one organic solvent is selected from the group consisting of esters, alcohols, ketones, glycol ethers, glycol ether esters, hydrocarbons, and combinations thereof.

5. The composite paper according to claim 4, wherein the at least one organic solvent is an organic solvent mixture of a first organic solvent having a boiling temperature greater than 90°C and a second organic solvent having a boiling temperature less than 90°C.

6. The composite paper of claim 5, wherein the organic solvent mixture comprises at least 5 wt.% of the first organic solvent.

7. The composite paper of claims 1 to 6, wherein the paper substrate is selected from the group consisting of tracing paper, writing paper, bond paper, text paper, cover paper, kraft paper, security paper, and paperboard.

8. The composite paper of claims 1-7, wherein the coating further comprises a thermoplastic acrylic resin.

9. The composite paper according to claims 1 to 8, wherein the composite paper exhibits one or more of the following properties: The haze value measured according to ASTM D1003 is less than 90%; A total transmittance value of at least 80% as measured according to ASTM D1003; and / or The transmission parallel and narrow angle light values ​​measured according to ASTM D1003 are greater than 4%.

10. An article made of the composite paper according to claims 1 to 9.

11. The article of claim 10, wherein the article is one or more of recyclable, compostable, or biodegradable.

12. A method for producing the composite paper according to claims 1 to 9, the method comprising: providing a paper substrate having a top surface and a bottom surface; coating at least a portion of the top surface of the paper substrate with a composition; as well as drying the composition to form a coating; A composite paper is thereby formed.

13. A method for producing the composite paper according to claims 1 to 9, the method comprising: providing a paper substrate having a top surface and a bottom surface; Provide coating; as well as At least a portion of the top surface of the paper substrate is laminated with the coating to form a composite paper.

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