Method for producing highly thermoformable acrylic solid surfaces

Abstract

An article can be formed from a thermoformable composition comprising: a) about 35 wt% to about 95 wt% of an acrylic prepolymerized slurry; b) about 0 wt% to about 10 wt% of a comonomer; and c) about 5 wt% to about 65 wt% of a filler having an average particle size (d50) ranging from about 0.1 pm to about 50 pm; wherein a surface of the article has a gloss measurement at a 60° measurement angle ranging from about 0 gloss units to about 20 gloss units, and a roughness Ra ranging from about 1 microinch to about 100 microinch. A method can include producing a thermoformed article by: i) preparing a thermoformable composition; ii) casting the thermoformable composition into a sheet; and iii) thermoforming the cast sheet against a mold to produce a thermoformed article.

Description

Background Technology

[0001] Textured and non-slip surfaces are produced using thermoformable acrylic resins or other plastic materials for wet areas such as swimming pools, kitchens, and bathrooms. In some cases, textured surfaces are created by roughening the plastic surface and then adding microparticles or other materials to give the liquid or molten acrylic resin a rough surface. However, subsequent processing of the roughened plastic surface through stretching or thermoforming to create thinner surfaces and complex shapes can reduce or eliminate the characteristics of the textured surface. Adding microparticles can also alter the surface stiffness and / or appearance, making the material more prone to defects during forming and bending, and more difficult to repair. Summary of the Invention

[0002] In one aspect, embodiments of this disclosure relate to articles formed from thermoformable compositions comprising: a) about 35 wt% to about 95 wt% of an acrylic prepolymer slurry; b) about 0 wt% to about 10 wt% of a comonomer; c) about 5 wt% to about 65 wt% of a filler having an average particle size (d50) in the range of about 0.1 μm to about 50 μm; wherein the surface of the article has a gloss measurement at a 60° measurement angle in the range of about 0 gloss units to about 20 gloss units, and a roughness Ra in the range of about 1 microinch to about 100 microinches.

[0003] In another aspect, the method relates to producing thermoformed articles by the following steps: i.) preparing a thermoformable composition comprising: a) about 35 wt% to about 95 wt% of an acrylic prepolymer slurry; b) about 0 wt% to about 10 wt% of a comonomer; c) about 5 wt% to about 65 wt% of a filler having an average particle size (d50) in the range of 0.1 μm to 50 μm; ii) casting the thermoformable composition into a sheet; and iii) thermoforming the cast sheet against a die to produce a thermoformed article, wherein the surface of the article has a gloss measurement value at a measurement angle of 60° in the range of about 0 gloss units to about 20 gloss units, and a roughness Ra in the range of about 1 microinch to about 100 microinches. Detailed Implementation

[0004] This disclosure relates to thermoformable compositions for producing textured, rough, or "non-slip" polymeric surfaces. The thermoformable compositions disclosed herein include compositions with increased thermoformability by controlling the ratio of average particle size and filler content to the polymer matrix, which can produce solid surfaces with small radius angles that are impossible to achieve with conventional acrylic formulations. Furthermore, these thermoformable compositions are easily repaired by scratches or stains, form a matte appearance upon stretching or thermoforming, and have a pleasant tactile feel. On the other hand, the thermoformability of polymeric surfaces can also be enhanced by adjusting the molecular structure of the material by controlling the density of intramolecular and intermolecular crosslinks between the polymer matrix and / or filler particles.

[0005] Comparative thermoforming methods for producing polymeric surfaces with matte appearance and textured finishes typically employ mechanical methods of surface roughening, such as casting or extrusion processes on liquid or molten acrylic to produce textured sheets, or by sanding or abrasion. However, mechanical methods are often limited in end-use applications because downstream processing, such as stretching or heating to form polymeric surfaces with more complex shapes, can alter or reduce the surface texture. Chemical methods that modify the polymer formulation components can also be used to prepare rigid polymeric surfaces capable of withstanding processing and sanding. For example, acrylic solid surfaces are formulated with high concentrations of metal oxides, which provide a rigid surface, but the increased surface rigidity limits thermoformability and restricts draft angles, thus lower angles are prone to cracking and stress whitening at bending locations.

[0006] The thermoformable compositions disclosed herein comprise polymer-forming compositions containing one or more fillers with reduced particle size and concentration. The reduced filler concentration improves the thermoformability of the solid surface while maintaining its strength to withstand machining techniques, such as sanding (e.g., with 320-grit sandpaper) or creating the solid surface on a matte film. Compared to compositions with higher filler concentrations, the disclosed compositions exhibit enhanced thermoformability, allowing the composition to fold itself during thermoforming without loss of texture, cracking, or stress whitening, regardless of the color of the solid surface material. The disclosed thermoformable compositions can be used to produce distinctive, rough, and “non-slip” surfaces for residential and commercial applications, including sheets and articles with thicknesses ranging from 1.5 mm to 10 mm or greater.

[0007] The thermoformable compositions disclosed herein include an acrylic prepolymer slurry matrix, which may also include one or more comonomers or copolymers. The acrylic prepolymer slurry may be included in about 35-95 wt% of the thermoformable composition. In some embodiments, the acrylic prepolymer slurry may include 5-40 wt% of solids. The acrylic prepolymer slurry may include polymers and oligomers with a weight-average molecular weight in the range of 10k-450k g / mol. In some cases, such as when the filler particle size is small (e.g., <2.0 μm) and / or for compositions with high filler content (e.g., >20 wt%), the thermoformable composition may contain an acrylate monomer matrix. For example, a thermoformable composition utilizing an acrylate monomer matrix may include filler with a particle size of about 0.9 μm and a weight percentage of about 50 wt%.

[0008] Thermoformable compositions may include one or more comonomers, copolymers, or additional prepolymers in a weight percentage (wt%) ranging from about 0 to 10 wt%. Suitable comonomers (and the polymers and prepolymers formed therefrom) may include additional acrylate and methacrylate monomers, such as methyl acrylate, butyl acrylate, benzyl acrylate, methyl methacrylate, and derivatives thereof. For thermoformable compositions containing copolymers or additional prepolymers, the copolymers or additional prepolymers may have a weight-average molecular weight in the range of 10 kJ to 450 kJ / mol.

[0009] Thermoformable compositions can exhibit enhanced thermoformability and surface texture by controlling at least two variables, either individually or simultaneously: the properties of the added filler; and the control of the molecular structure of the polymer matrix. Each method will be described in more detail below.

[0010] In some embodiments, surface texture and thermoformability can be controlled by including fillers having a defined average particle size, said fillers being combined to balance the ratio of durability of post-processed surface features to thermoformability. The thermoformable composition may include one or more fillers added in a weight percentage ranging from 5 wt% to 65 wt%. In some embodiments, the filler-to-acrylic prepolymer slurry ratio is in the range of 0.05 to 1.9. Suitable fillers may include metal oxides such as alumina trihydrate (ATH), aluminum monohydrate, magnesium hydroxide, magnesium silicate, talc, silica such as fumed silica and precipitated silica, calcium carbonate, calcium metasilicate, wollastonite, dolomite, perlite, hollow glass spheres, kaolin, etc.

[0011] In some embodiments, the particle size of the filler can be used to control both surface texture and appearance. Larger particle sizes are generally associated with increased surface roughness and rigidity, while smaller particle sizes may be associated with reduced gloss and increased matte appearance. The thermoformable compositions disclosed herein may comprise fillers with an average particle size (d50) in the range of 0.1 μm to 50 μm, 1 μm to 25 μm, or 2 μm to 17 μm as determined by a laser diffraction particle size analyzer. While particle size calculations may assume an equivalent spherical shape, the filler particle shape is not limited and may include shapes such as spherical, hemispherical, oval, polyhedral, fibrous, cylindrical, etc. As the d50 of the particles decreases, the hygroscopicity and potential moisture content of the filler increase. An increase in moisture content in the filler leads to an increase in moisture content in the final product (e.g., sheet or article), resulting in downstream defects such as blistering. To reduce defects, the thermoformable compositions may comprise fillers that are obtained having or dried to include a moisture content of less than 1 wt%, 0.5 wt%, or 0.3 wt%.

[0012] The packing material disclosed in this article may have a size greater than approximately 1 m 2 / g, greater than approximately 2m 2 / g or greater than approximately 3m 2 / g BET surface area. In some embodiments, the packing may have a BET surface area of ​​approximately 1m². 2 / g to approximately 5m 2 / g, or approximately 2m 2 / g to approximately 4m 2 BET surface area within the range of / g. Surface area analysis can be performed using any suitable technique, including via Quantachrome MONOSORB. TM Surface analyzer. In a particular embodiment, the filler particles may have a d50 particle size in the range of about 2 μm to about 20 μm and a particle size greater than about 1 μm. 2 The BET surface area disclosed herein is approximately 2.3 g / cm³. 3 Approximately 2.5 g / cm³ 3 The specific gravity is within the range of approximately 0.4 g / cm³. 3 To approximately 0.95 g / cm 3 The packing density within the range.

[0013] In some implementations, surface texture and thermoformability can be controlled by adjusting the molecular structure of the polymer matrix (which is achieved by adjusting the molecular weight of the constituent polymer chains of the matrix) and / or controlling the concentrations of crosslinking and coupling agents to regulate the density of intra- and inter-chain crosslinks. By adjusting the molecular structure of the acrylic matrix, the overall rigidity of the material is reduced to enhance thermoformability, while also balancing the durability and chemical resistance of the solid surface.

[0014] For the cross-linked solid surface resulting from processing thermoformable compositions, the molecular weight and degree of cross-linking of the polymer matrix are characterized by the thermoformability parameter (Q value) used to describe the swelling ratio of the cross-linked acrylic acid. The Q value is described according to Equation 1:

[0015] Q value = (Wt + We / Ds) + 0.1Wo / Do (1)

[0016] Where Q is the swelling ratio, Wt is the weight of the swollen polymer at equilibrium, We is the weight of the extracted material, Ds is the density of the solvent (dichloromethane = 1.336), Wo is the weight of the original sample, and Do is the density of the polymer (acrylic acid = 1.2). Generally, a lower Q value indicates an increased crosslinking density. In some embodiments, the thermoformable compositions disclosed herein can be thermoformed to form articles having a Q value in the range of 5 to 25.

[0017] The thermoformable composition may contain one or more coupling agents that increase the dispersibility of fillers and polymer matrices. In some embodiments, the thermoformable composition may contain one or more coupling agents in the range of 0.05wt% to 1.0wt%, 0.05wt% to 0.75wt%, or 0.10wt% to 0.50wt% by weight percentage (wt%).

[0018] Suitable coupling agents may include 3-methacryloyloxypropyltrimethoxysilane, 2-hydroxyethyl methacrylate, 8-methacryloyloxyoctyltrimethoxysilane, and reactive polymer coupling agents such as BYK-C 8002 and polypropylene glycol phosphate Sipomer PAM200.

[0019] The thermoformable composition may also contain a crosslinking agent having two or more vinyl groups capable of forming intramolecular and intermolecular crosslinks within an acrylic matrix during processing and / or thermoforming. Suitable crosslinking agents include ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate such as PEG200 and PEG600 dimethacrylate, trimethylolpropane-tri-methacrylate (TRIM), triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc. In some embodiments, the thermoformable composition may contain one or more coupling agents in the range of 0.05 wt% to 1.5 wt%, 0.05 wt% to 1.5 wt%, or 0.05 wt% to 1.5 wt%.

[0020] Thermoformable compositions may also include a variety of functional additives to initiate and control various properties of the thermoforming reaction, including initiators, chain transfer agents, wetting / dispersing agents, antiflocculation agents, pigments, release agents, degassing agents, suspending agents, etc.

[0021] Table 1 provides formulation guidelines for producing the thermoformable compositions disclosed herein.

[0022]

[0023] The thermoformable composition can be processed into textured solid surfaces or articles by combining the components in Table 1 and thermoforming using any suitable continuous or batch technique, including continuous casting, unit casting, extrusion, or other suitable methods. After combination, the thermoformable composition may optionally be degassed in a vacuum. The degassed thermoformable composition is then processed using a chosen method, such as pouring it into a unit or a continuous casting machine. In some embodiments, the thermoformable composition is heated to 185℉ and held for a suitable period, such as 20 minutes, to initiate polymerization. The thermoformable composition is then transferred to a unit and heated in a forced-air oven at 240℉ for 12 minutes. If casting is performed against a highly polished surface, the final article will have a high gloss finish upon cooling. In some embodiments, the surface and article can be thermoformed against a mold, wherein the included filler provides surface texture as the article is stretched and thinned.

[0024] Table 2 provides an exemplary range of thermoformed surfaces or articles prepared in accordance with this disclosure.

[0025]

[0026] The thermoformable compositions disclosed herein can be processed to form textured surfaces or articles for a wide range of commercial and residential applications, including surfaces for wet areas such as sinks, bathtubs, shower trays, etc.; building surfaces; and various building components. While the compositions disclosed herein are described in terms of their use and function in thermoforming applications, various molding processes can be applied to produce thermoformed sheets or articles, including processes selected from: extrusion molding, co-extrusion molding, extrusion coating, injection molding, injection blow molding, injection stretch blow molding, thermoforming, cast film extrusion, blown film extrusion, foaming, extrusion blow molding, injection stretch blow molding, rotational molding, pultrusion, calendering, additive manufacturing, lamination, etc.

[0027] Generally, stretching or pulling sheets made from thermoformable compositions during the thermoforming process can alter surface characteristics and change gloss values, resulting in a matte appearance. For example, in products such as hot tubs, the gloss value of the deck area where the material is stretched the least may be higher than that of the sides and bottom of the tub where it is stretched more. Consumers may prefer a uniform appearance, and additional processing can be applied to the product to enhance the matte finish, such as sanding, media blasting, embossing patterns onto the sheet, unit casting between sheets, casting on a matte film, acid etching, etc. For example, sanding the sheet with 320-grit sandpaper can produce a uniform matte appearance on thermoformed products.

[0028] The surface gloss of articles made from the thermoformable compositions disclosed herein can be quantified by any suitable method known in the art, such as measurement at a 60° measurement angle using a BYK-Gardner gloss meter. In some embodiments, the thermoformable compositions can be processed into articles or surfaces having a gloss value at a 60° measurement angle of less than about 20 gloss units, less than about 15 gloss units, or less than about 10 gloss units.

[0029] In addition to appearance, the texture of articles made from the thermoformable compositions disclosed herein can be modified to achieve tactile properties within desired specifications. The surface produced by the thermoformable composition can be quantified using roughness Ra, defined as the arithmetic mean height of roughness irregularities measured from an average line over an evaluation length. Roughness Ra can be measured using commercially available instruments, such as the Mahr Pocket Surf IV portable surface roughness meter. In some embodiments, the thermoformable composition can be processed into articles or surfaces with roughness Ra less than about 100 microinches, less than about 50 microinches, or less than about 30 microinches.

[0030] Articles made from the thermoformable compositions disclosed herein may have gloss and roughness measurements within any of the foregoing values. In a particular embodiment, the thermoformable compositions disclosed herein may have gloss measurements at a 60° measurement angle ranging from about 0 gloss units to about 20 gloss units, and roughness Ra ranging from about 1 microinch to about 100 microinches.

[0031] All documents described herein are incorporated herein by reference for the purpose of all jurisdictions where such practice is permitted, including any priority documents and / or test procedures, to the extent that they are not inconsistent with this document. It will be apparent from the foregoing general description and specific embodiments that various modifications may be made without departing from the spirit and scope of this disclosure, although the form of this disclosure has been described and illustrated. Therefore, this disclosure is not intended to be limited thereto. For example, the compositions described herein may not contain any components or compositions not expressly listed or disclosed herein. Any method may omit any steps not listed or disclosed herein. Similarly, the term “comprising” is considered synonymous with the term “including.” Whenever a transitional phrase “comprising” precedes a method, composition, element, or group of elements, it should be understood that we also consider the same composition or group of elements preceding the description of the composition, one or more elements with the transitional phrases “consistently constitutes,” “composes of,” “selected from the group of,” or “is,” and vice versa.

[0032] This document presents one or more illustrative embodiments containing one or more inventive elements. For clarity, not all features of the physical implementation are described or shown in this application. It should be understood that in the development of a physical embodiment containing one or more elements of the invention, many implementation-specific decisions must be made to achieve the developer's objectives, such as complying with system-related, business-related, governmental-related, and other restrictions that vary depending on the implementation and time. Although the developer's efforts may be time-consuming, such efforts will be routine for those skilled in the art and who benefit from this disclosure.

[0033] Unless otherwise stated, all figures used in this specification and related claims to indicate the amount or characteristics of components, such as molecular weight, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximate values ​​that may vary depending on the desired characteristics sought to be obtained according to embodiments of the invention. To the minimum extent necessary and without attempting to limit the scope of equivalence of the claims, each numerical parameter should be interpreted at least based on the reported significant figures and by applying ordinary rounding techniques.

[0034] Whenever a numerical range with a lower and upper limit is disclosed, any number belonging to that range and any range included therein, including both the lower and upper limits, is specifically disclosed. Specifically, each range of values ​​disclosed herein (in the form of “about a to about b,” or equivalently, “about a to b,” or equivalently, “about ab”) is understood to represent each value and range included within a broad range of values. Furthermore, unless otherwise expressly and clearly defined by the patentee, terms in the claims have their ordinary, common meaning. Additionally, the indefinite article “a / an” as used in the claims is defined herein to refer to one or more elements it introduces.

[0035] Therefore, this disclosure is well-suited to achieving the stated objectives and advantages, as well as those inherent herein. The specific embodiments disclosed above are merely illustrative, as this disclosure can be modified and practiced in different but equivalent ways that will be readily apparent to those skilled in the art and who have benefited from the teachings herein. Furthermore, it is not intended to limit the details of the constructions or designs shown herein beyond those described in the following claims. It will therefore be apparent that the specific illustrative embodiments disclosed above can be altered, combined, or modified, and all such changes are considered to be within the scope and spirit of this disclosure. The embodiments of the illustrative disclosure herein may be suitably practiced in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein.

Claims

1. An article formed from a thermoformable composition, said thermoformable composition comprising: a) 35 wt% to 95 wt% acrylic acid prepolymer slurry; b) 0 wt% to 10 wt% comonomers; and c) 5 wt% to 65 wt% of filler having an average particle size (d50) in the range of 2 μm to 50 μm; The surface of the article described herein has a gloss measurement value at a 60° measurement angle in the range of 0 gloss units to 20 gloss units, and a roughness Ra in the range of 1 microinch to 100 microinches. The filler is selected from one or more of the following: aluminum trihydrate, aluminum monohydrate, magnesium hydroxide, calcium carbonate, magnesium silicate, talc, silicon dioxide, calcium metasilicate, wollastonite, dolomite, perlite, hollow glass spheres, and kaolin.

2. The article of claim 1, wherein the ratio of filler to acrylic prepolymer slurry is in the range of 0.05 to 1.

9.

3. The article of any one of claims 1 to 2, wherein the filler has a d50 particle size in the range of 2 μm to 20 μm and a particle size greater than 1 μm. 2 / g of BET surface area.

4. The article of any one of claims 1 to 2, wherein the filler has a density greater than 3 μm. 2 / g of BET surface area.

5. The article of any one of claims 1 to 2, wherein the solid weight percentage (wt%) of the acrylic prepolymer slurry is in the range of 5 wt% to 40 wt%.

6. The article of any one of claims 1 to 2, wherein the comonomer is butyl acrylate.

7. The article of claim 1 to 2, wherein the article has a Q value in the range of 5 to 25, wherein the Q value is described according to Equation 1: Q value = (Wt + We / Ds) + 0.1 Wo / Do (1) Where Q is the swelling ratio, Wt is the weight of the swollen polymer at equilibrium, We is the weight of the extracted material, Ds is the density of the solvent, Wo is the weight of the original sample, and Do is the density of the polymer.

8. The article of any one of claims 1 to 2, wherein the thermoformable composition comprises: a) 35 wt% to 95 wt% acrylic acid prepolymer slurry; b) 0 wt% to 10 wt% comonomer; c) 5 wt% to 65 wt% of filler, wherein the filler has an average particle size (d50) in the range of 2 μm to 50 μm; d) 0.0 wt% to 1.0 wt% coupling agent; and e) 0.1 to 1.0 wt% of crosslinking agent.

9. The article of any one of claims 1 to 2, wherein the filler contains less than 1.0 wt% moisture.

10. The article of any one of claims 1 to 2, wherein the thermoformable composition further comprises one or more of the following: wetting / dispersing agents, antiflocculating agents, pigments, release agents, degassing agents, suspending agents, and initiators.

11. The article of any one of claims 1 to 2, wherein the article has a content greater than 1.3 g / cm³. 3 The density.

12. A method for producing thermoformed articles, the method comprising the following steps: i) Preparing a thermoformable composition, said thermoformable composition comprising: a) 35 wt% to 95 wt% acrylic acid prepolymer slurry; b) 0 to 10 wt% comonomers; and c) 5 to 65 wt% of filler, wherein the filler has an average particle size (d50) in the range of 2 μm to 50 μm; ii) Cast the thermoformable composition into sheets; as well as iii) The cast sheet is thermoformed against a die to produce a thermoformed article, wherein the surface of the article has a gloss measurement value at a 60° measurement angle in the range of 0 gloss units to 20 gloss units, and a roughness Ra in the range of 1 microinch to 100 microinches.

13. The method of claim 12, further comprising modifying the surface of the thermoformed article by one or more of the following: sanding, media blasting, embossing a pattern on the article, inter-plate casting, casting on a matte film, and acid etching.

14. The method of any one of claims 12 to 13, wherein the ratio of filler to acrylic prepolymer slurry is in the range of 0.05 to 1.

9.

15. The method of any one of claims 12 to 13, wherein the solid weight percentage (wt%) of the acrylic prepolymer slurry is in the range of 5 wt% to 40 wt%.

16. The method of any one of claims 12 to 13, wherein the thermoformed article has a Q value in the range of 5 to 25 after thermoforming, wherein the Q value is described according to Equation 1: Q value = (Wt + We / Ds) + 0.1 Wo / Do (1) Where Q is the swelling ratio, Wt is the weight of the swollen polymer at equilibrium, We is the weight of the extracted material, Ds is the density of the solvent, Wo is the weight of the original sample, and Do is the density of the polymer.

17. The method of any one of claims 12 to 13, wherein the filler has a d50 particle size in the range of 2 μm to 20 μm and a particle size greater than 1 μm. 2 / g of BET surface area.

Images