Composite material from cellulose and hydrogenated oils or fats

Abstract

A composite material is disclosed, comprising a mixture of hydrogenated oils or fats and cellulose fibers. This composition offers enhanced mechanical, thermal, and water-resistant properties compared to pure hydrogenated oils or fats and conventional moulded pulp, respectively, making it suitable for various applications, including but not limited to paper bottles, packaging, furniture inserts, burial coffins, construction, and arts and crafts. The composite is obtainable by first preparing an intermediate moulded article by conventional pulp moulding methods and submerging the moulded intermediate article in melted hydrogenated oils or fats.

Description

[0001] P15856PC00

[0002] Composite Material from Cellulose and Hydrogenated Oils or Fats

[0003] FIELD OF THE INVENTION

[0004] This invention relates to compositions of matter, specifically to a composite material comprised of moulded cellulose fibers and hydrogenated oils or fats useful for various rigid articles and structures, such as cartons, including paper-based bottles and other packaging materials that benefit from being water resistant.

[0005] BACKGROUND OF THE INVENTION

[0006] Pulp moulded packaging materials made of cellulosic pulp substrates with plastic coatings are known in the art. However, prior art materials have several disadvantages such as being difficult to recycle, not breaking down in the environment, lack of structural integrity and strength, and poor barrier performance.

[0007] Hydrogenated oils and fats are commonly used in the food industry in products like margarine, baked goods, and snack foods, as they provide a desirable texture and prevent spoilage. Hydrogenated oils and fats are types of fats created by the process of hydrogenation. This process involves adding hydrogen atoms to unsaturated fat molecules in order to make them more saturated. The primary reason for hydrogenating oils or fats is to change their physical properties, making them more solid at room temperature.

[0008] On the other hand, cellulose fibers have been widely used in paper, moulded pulp, textile, and other industries. Independently, both materials have unique properties. Moulded pulp is useful in many products such as protective packaging and various structural items, and has the general advantage that the material is biodegradable and easily recyclable. Moulded pulp, however, is sensitive to moisture and may lack sufficient tensile strength for heavy-weight support, in which case wood or fiberboard may need to be used, which is a much heavier and costlier alternative.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention pertains to a composite material comprising hydrogenated oils or fats and moulded cellulose fibers. This composition possesses enhanced mechanical, hydrophobic, thermal, and other properties, as compared to conventional moulded cellulose P15856PC00 fiber articles, making it suitable for various applications such as but not limited to paper bottles, general food and fresh produce containers, hospital bedpans, urinal paper bottles, transport pallets, moulded furniture, fish containers, meat containers, burial coffins and inserts into laminated furniture.

[0011] A benefit of using hydrogenated oils and fats in the composite of the invention is recyclability. Unlike moulded articles with added polymer barrier (plastic barrier), the composite of cellulose fibers and hydrogenated oils and fats breaks down easily e.g. in a hydropulper.

[0012] A beneficial surprise of the invention is the substantial increase in strength of moulded cellulose fiber articles after they have been made into the composite of the invention. Pallet feet made according to the invention showed in a conventional buckling load test increased buckling load by about 100%.

[0013] A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is made up of two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements. Useful composite materials enhance the properties of its base materials. Within the finished structure, the individual elements remain separate and distinct, distinguishing composites from mixtures and solid solutions.

[0014] Composites offer significant benefits in various material performance aspects, exceeding the mono-material alternatives and particularly stand-alone use of the constituent parts like a normal pulp moulded article in the case of the present invention. The result, in the case of the present invention, is a combined material that benefits from the tensile strength of the fiber reinforcer, the compressive strength of the matrix, and the bending strength of their marriage to make a strong, rigid, stiff, and bend-tolerant resultant material.

[0015] The composite material of the invention is light by nature and automatically sterilized in the manufacturing process. The material is fully recyclable provided the pulping process is at temperatures exceeding the melting temperature of the hydrogenated oils or fats and can be shredded and returned to a pulp mix, which in turn can be separated into an aqueous phase (with paper pulp) and organic phase (hydrogenated oils or fats).

[0016] The hydrogenated oils or fats matrix component not only provides a hydrophobic water repellent surface layer on the moulded products but penetrates the product to form an internal P15856PC00 matrix component. Advantageously and quite surprisingly, the introduction of the hydrogenated oils or fat component substantially increases the strength of the moulded product, compared with prior art moulded products, as mentioned above.

[0017] In a primary aspect the invention provides a composite material, comprising a mixture of hydrogenated oils or fats and cellulose fibers, wherein the cellulose fibers are uniformly distributed within the hydrogenated oils or fats matrix.

[0018] The hydrogenated oils or fats may be selected from but is not limited to hydrogenated canola oils, rape seed oils, olive oils, sunflower oils, soybean oils, peanut oils, sesame oils, corn oils, coconut oils, palm oils, flaxseed oils, grapeseed oils, walnut oils, avocado oils, almond oils, hemp seed oils, animal fat such as pig fats, beef fats, chicken fats, farmed salmon fats, oils from other farmed fish, or combinations thereof.

[0019] The cellulose fibers are preferably derived from wood pulp, cotton, hemp, bamboo, sugar cane fiber, flax fiber, fiber from grains, coconuts or other plant-based source.

[0020] Typically and preferably, the composite material of the invention comprises in the range of about 10-50 wt% hydrogenated oils or fats and preferably in the range of about 20-40% hydrogenated oils or fats, such as in the range from about 10% or from about 12% or from about 15%, or from about 20%, to about 50% or to about 45% or to about 40% or to about 35% or to about 30% or to about 25% of hydrogenated oils or fats (wt%).

[0021] Hydrogenated oils and fats offer the convenience over natural hard fats that the presence of unsaturated fats or oils can be substantially eliminated, and thus hydrogenated oils and fats can be used in the present disclosure without leaving any “greasy” effect on the surface if composite articles, as could happen when using natural fats that typically contain some minor amount of unsaturated fatty chains.

[0022] The main benefits of using hydrogenated oils and fats in the composite of fibers and oils or fats is besides the water resistance and added strength mentioned above, is recyclability, and in this regard hydrogenated oils and fats are preferred over wax, as the hydrophobic component of the composite pallet of the disclosure. The composite of cellulose fibers and hydrogenated oils and fats breaks down easily in a hydropulper. P15856PC00

[0023] As is apparent from the present disclosure, the composite material can be obtained by methods described herein, which generally comprise steps of first moulding said cellulose fibers in a pulp moulding process to obtain an intermediate dry moulded pulp article, and subsequently by submerging said intermediate moulded pulp article in melted hydrogenated oils or fats to allow the hydrogenated oils or fats to impregnate the moulded pulp article, recovering the article and allowing said article to dry, which comprises said composite material.

[0024] In some embodiments of the invention spraying the hot hydrogenated oils and fats on to the intermediate moulded pulp article is applied. Spraying the hot hydrogenated oils at temperature in the range from 90°C to 170°C will result in composite formation on moulded pulp surfaces.

[0025] The pulp moulding processes applicable in the invention are as such known in the art. Thus, the source pulp may be made by a conventional pulping method where virgin fiber or wastepaper or other fiber source is placed into a hydro pulper. Consistency of between 2 to 5% dry matter is typically used during pulping process or up to 18% if using high consistency pulper. The pulp is later diluted down to 0,7% to 1 ,7% in a moulding machine. The moulding process is preferably a conventional vacuum forming method where a mould (tool) is dipped into the pulp mixture, vacuum is applied to the mould comprising a product shape and wire mesh screen. The screen filters out fiber onto the shaped mould. The mould is transferred out from the pulp mixture and dewatering takes place. After about 4 to 30 seconds of dewatering the resulting article has a fiber content of about 27 to 35% fiber and thus about 65% to 73% water. The wet intermediate article is then moved to a drying station. There are multiple types of drying stations known in the art and applicable in the present invention. The most common is a convection oven operating at a temperature of 160°C to 230°C. Another drying method is applying microwaves to dry the product. A third method is to place the wet intermediate article into a heated pressure tool set comprising male and female die parts. The wet intermediate article is placed between the tool parts and heat is transferred into the fiber web drying the intermediate article to 3% to 9% humidity level. After the drying, whichever method is applied, the dry intermediate article is now ready as an intermediate to be further processed into the composite material.

[0026] The conditions and specifications of the pulp material and the pulp moulding process can be selected and optimized depending on the type of article being made, for example, the compression force applied in the moulding machine and other factors such as source of pulp material may affect the density and microscopic characteristics of the intermediate object, P15856PC00 which in turn will affect how much hydrogenated oils or fats will be absorbed by the object in the step of soaking in the bath of hot hydrogenated oils or fats.

[0027] The next step is to soak (submerge) the intermediate article in liquid hydrogenated oils or fats, preferably by dipping (submerging) the article into a bath of melted liquid hydrogenated oils or fats, preferably at a temperature in the range from 50°C to 190°C, such as preferably in the range from 110°C to 190°C, such as from about 50°C or from about 60°C or from about 70°C or from about 80°C or from about 90°C or from about 100°C or from about 110°C or from about 120°C or from about 130°C, to about 190°C or to about 180°C or to about 170°C or to about 160°C or to about 150°C. The minimum melting temperature depends i.a. on the melting point of the selected hydrogenated oils or fats, as the temperature must be sufficient to fully melt the oils or fats and preferably is above the melting point by at least 5°C or more preferably by at least 20°C. In some embodiments, however, a substantially higher temperature is used for the bath than the melting temperature, such as but not limited to a temperature which is in the range of 50° to 100°C higher than the melting point of the oils or fats used. A high temperature such as in the mentioned ranges is preferred as this lowers the viscosity of the oils and enhances its penetration into the intermediate article. The hot liquid hydrogenated oils or fats will penetrate the intermediate article, and flow in between the cellulose fibers, creating a matrix of hydrogenated oils or fats and reinforcement from moulded cellulose (moulded pulp) thus forming a composite material of great strength.

[0028] Accordingly, the composite material of the invention generally and preferably exhibits improved mechanical strength, hydrophobic character, thermal stability, or water resistance compared to pure hydrogenated oils or fats and conventional moulded pulp, respectively.

[0029] In another aspect of the invention, a rigid composite article is provided and encompassed by the invention, comprising composite material according to the invention, such as described and defined herein.

[0030] In yet a further aspect, the invention provides a method of preparing the composite material of the invention or a rigid composite article of the invention, comprising the steps of:

[0031] - obtaining oils or fats and cellulose fiber;

[0032] - hydrogenating oils or fats (these can alternatively advantageously also be obtained as a hydrogenated intermediate product, from several suppliers);

[0033] - moulding fiber into a shape via pulp moulding method;

[0034] - drying the moulded pulp shape into an intermediate article, P15856PC00 melting the hydrogenated oils or fats and heating to desired temperature;

[0035] - submerging said intermediate article into the melted hydrogenated oils or fats for sufficient time to allow the hydrogenated oils or fats to penetrate and impregnate the intermediate article, and

[0036] - recovering the impregnated article and allowing the obtained article comprising the composite material to cool and solidify.

[0037] Preferably the step of drying may be selected from drying in drying press mould, and drying in convection oven, as mentioned above.

[0038] Time in the hydrogenated oils or fats bath is preferably in the range from a minimum of 1 second and up to 20 seconds but more preferably at least 2 seconds, such as in the range of 2 to 20 seconds. Typically, after about 20 seconds essentially no further hydrogenated oils or fats penetration is achieved, though this may depend on the temperature and viscosity of the selected hydrogenated oils or fats matrix. Accordingly, the submerging step may in some embodiments take in the range from 1 sec. or 2 sec. or 3 sec. or 5 sec. to about 20 sec or 18 sec or 15 sec. Longer submerging times may as well be applied if desired e.g. for logistic purposes, such as in the range from 20 sec. or in the range from 30 sec. to about 60 sec.

[0039] Spraying the hydrogenated oils or fats is an option. This creates a matrix layer of between 0,5mm up to 2mm deep. Thus, with this embodiment articles can be obtained that comprise the composite of the invention as an outer layer extending about 0,5 to 2 mm into the article, and beyond the outer composite layer is non-penetrated moulded cellulose, depending on the overall thickness of the walls of the object. Thus, in some embodiments moulded articles such as bottles, boxes and trays can be moulded and then at least the inside surface of the articles (the surface intended to be in contact with liquid or wet material) can be sprayed with hydrogenated oils or fats, but optionally also the outside.

[0040] Another aspect of the invention provides and encompasses the use of the composite material of the invention, in an application selected from packaging material, furniture or parts thereof such as furniture inserts, construction, and art and crafts, trays, cartons, including paperbased bottles, and burial coffins.

[0041] DETAILED DESCRIPTION OF THE INVENTION

[0042] 1. Composition: P15856PC00

[0043] Hydrogenated oils or fats: The hydrogenated oils or fats component can comprise any hydrogenated oils or fats including but not limited to canola oils, rape seed oils, olive oils, sunflower oils, soybean oils, peanut oils, sesame oils, corn oils, coconut oils, palm oils, flaxseed oils grapeseed oils, walnut oils, avocado oils, almond oils, hemp seed oils, animals fat such as pig fats, beef fats, chicken fats, farmed salmon fats, farmed fish oils or combinations thereof. The hydrogenated oils or fats material (matrix) can comprise one or more of various forms of hydrogenated oils or fats. Hydrogenated oils or fats are a colorless solid derived from hydrogenating oils or fats that consists of a mixture of hydrocarbon molecules. Hydrogenated oils, which include partially and fully hydrogenated oils, are types of fats used in various food products. The number of carbon atoms in hydrogenated oils can vary widely because these oils are derived from various sources such as vegetable oils such as the above mentioned or animal fats. These oils are composed of triglycerides, which are molecules made up of a glycerol backbone bonded to three fatty acid chains. The fatty acids in these oils, which determine the number of carbon atoms, typically have anywhere from 12 to 22 carbon atoms, depending on the source of the oil and the specific fatty acids it contains. In some embodiments the hydrogenated oils are selected to be relatively homogeneous, e.g. with only one, two or three major fatty acid constituents. In other embodiments the hydrogenated oils may comprise a relatively heterogeneous mixture of fatty acids. The hydrogenated oils or fats material is solid at room temperature and begin to melt at different temperature depending on the fatty acid composition and degree of hydrogenation, but generally at a temperature above about 38°C and can typically have a melting point in the range between about 46° and 90°C. Various polymers can be added to the hydrogenated oils or fats to enhance the strength and / or alter the properties of the composite in other ways. Preferably such added polymer(s) are selected to be biodegradable. Accordingly, in some embodiments of the invention the composite comprises one or more polymer component.

[0044] Hydrogenated oils are manufactured from many different sources and mixtures such as those mentioned above. In the present invention it is preferred to select a hydrogenated oil with a relatively low melting point, such as but not limited to having a melting point in the range 50- 70°C or in the range 60-70°C, such as about 55°C, 58°C, 60°C, 62°C or 65°C. The melting point should be such that the materials remain fully solid at any typical temperatures that respective objects made from the composite may withstand during normal use. However, selecting a hydrogenated oils composition with relatively low melting point, such as those mentioned just above makes recycling of the objects of the invention easier and quicker.

[0045] Cellulose Fibers: The cellulose fibers can be derived from sources such as but not limited to wood pulp, cotton, hemp, or any other plant-based fiber rich sources. The process of the P15856PC00 invention is applicable to various natural cellulose fiber material such as but not limited to wood-based fiber, hemp, bamboo, cotton fiber, sugar cane fiber, coconut fibers, fibers from grains and straw material. These fibers can be refined, unrefined, bleached, unbleached, or treated in any other manner.

[0046] 2. Preparation: a. The hydrogenated oils or fats material is melted, typically and preferably to a temperature in the range from about 90°C up to about 190°C, appropriate for its type. b. Cellulose fibers are moulded into a shaped article, through traditional pulping process with vacuum being applied to a mould that filters out fibers from a slurry composed of water and in the range 0,7% to 1 ,5% fiber. The moulded wet product is after the vacuum forming composed of in the range of approximately 29% to 34% fiber and in the range of about 71% to 66% water. The moulded article is then dried, preferably either in a thermoforming tool, a traditional convective air dryer or a microwave dryer. c. The composite is created by dipping the dry moulded article into a bath of melted hydrogenated oils or fats. The hydrogenated oils or fats impregnates the cellulose structure and reinforces the web of intertwined cellulose fibers. Once thoroughly blended, the composite is allowed to cool and solidify.

[0047] 3. Properties:

[0048] The resulting hydrogenated oils or fats-cellulose composite has enhanced properties compared to either solid hydrogenated oils or fats or moulded cellulose alone. These can include: a. Improved mechanical strength due to the reinforcing nature of cellulose fibers and the embedding of the fibers in the hydrogenated oils or fats matrix. b. Enhanced thermal stability because of the heat-resistant nature of cellulose. c. Much improved water resistance.

[0049] 4. Potential Applications:

[0050] The hydrogenated oils or fats -cellulose composite can be used in various applications such as but not limited to: P15856PC00 a. Paper bottles that are liquid resistant; b. Packaging: providing water-resistant and biodegradable packaging alternatives; c. Hospital trays like bed pans and urinal bottles; d. Inserts into composite wood structures such as furniture, e.g. bookshelves, cabinets and more; e. Moulded paper burial coffins; f. Construction: as insulation or protective coatings or sheets.

[0051] EXAMPLE

[0052] Example 1

[0053] As a non-limiting illustrative example, the production of an article comprising the composite of the invention is described, referring to accompanying figures. This example is provided to provide further understanding of the invention, without limiting its scope.

[0054] Figure 1 depicts a schematic overview of a process for making an article of the invention, which in this particular example is a transport pallet.

[0055] 1) A hydro pulper 1 produces a pulp with consistency in the range of 2-18% solids.

[0056] 2) The pulp is pumped into pulp storage tank 2.

[0057] 3) Pulp and white water (from preceding steps, stored in white water tank 3) is blended to create a suitable pulp for the forming tank 4.

[0058] 4) A pulp article 6 is vacuum formed in the forming tank 4 by applying vacuum and article shaped moulds 5.

[0059] 5) The obtained wet pulp article 6 is dried in a set of thermo dies 7a, 7b (hot pressing molds).

[0060] 6) The dry pulp article 8 is transferred to a hydrogenated oils or fats bath 9 with heated hydrogenated oils or fats, impregnating the fiber base to create a composite material.

[0061] 7) The finalized composite article 10 is cooled and ready for use.

[0062] An option to step 5) is to transfer the wet moulded article into a convection oven or a microwave dryer before entering the hydrogenated oils or fats bath.

[0063] Example 2

[0064] Pallet feet were moulded in conventional moulding process as described above. After drying, two specimens were dipped in hot wax bath (145°C) with paraffin wax and other two specimens left untreated. After cooling and drying, the pallet feet were subjected to P15856PC00 conventional buckling load test. (Wax has been found by the inventor to give in the composite of the invention substantially similar products in terms of strength, durability and hydrophobicity but proves more difficult to recycle than the composite of the invention with hydrogenated oils or fats.)

[0065] The result is shown in Table 1 and shows that the feet specimen from the pulp-wax composite have on average 102% higher buckling load.

[0066] Table 1 This demonstrates that not only does the invention provide objections with good water resistance but very substantial increase in strength.

Claims

P15856PC00CLAIMS1 . A composite material, comprising a mixture of hydrogenated oils or fats and cellulose fibers, wherein the cellulose fibers are uniformly distributed within the hydrogenated oils or fats matrix.

2. The composite material of claim 1 , wherein the hydrogenated oils or fats comprise oils and / or fats selected from the group consisting of canola oils, rape seed oils, olive oils, sunflower oils, soybean oils, peanut oils, sesame oils, corn oils, coconut oils, palm oils, flaxseed oils grapeseed oils, walnut oils, avocado oils, almond oils, hemp seed oils, animals fat such as pig fats, beef fats, chicken fats, farmed salmon fats, farmed fish oils, and combinations thereof.

3. The composite material of claim 1 or 2, wherein the cellulose fibers are derived from wood pulp, cotton, hemp, bamboo, sugar cane fiber, flax fiber, fiber from grains, or other plant-based source.

4. The composite material of any of the preceding claims comprising in the range of 10-50 wt% of said hydrogenated oils or fats and preferably in the range of 20-40 wt% of said hydrogenated oils or fats.

5. The composite material of any of the preceding claims wherein said hydrogenated oils or fats have a melting point in the range in the range 50-70°C.

5. The composite material of any of the preceding claims, obtainable by first moulding said cellulose fibers in a pulp moulding process to obtain an intermediate moulded pulp article, and subsequently by submerging said intermediate moulded pulp article in full or partially in a bath of melted hydrogenated oils or fats, or by spraying said melted hydrogenated oils or fats on to said intermediate moulded pulp article to allow the hydrogenated oils or fats to impregnate the moulded pulp article, recovering the article and allowing said article to dry, which comprises said composite material.

6. The composite material of claim 5, wherein an intermediate article is obtained by pulp vacuum moulding process and the obtained intermediate article is subjected to impregnation and penetration by said hydrogenated oils or fats.P15856PC007. The composite material of any of the preceding claims, exhibiting improved mechanical strength, thermal stability, or water resistance compared to corresponding moulded pulp intermediate article that has not been treated with said hydrogenated oils or fats.

8. A rigid composite article comprising composite material according to any of claims 1 to 7.

9. A method of preparing a composite material of any of claims 1-7 or the rigid composite article of claim 8, comprising the steps of:- obtaining hydrogenated oils or fats and cellulose fiber,- moulding fiber into a shape via pulp moulding method,- drying the moulded pulp shape into an intermediate article,- melting said hydrogenated oils or fats,- submerging said intermediate article into the melted hydrogenated oils or fats for sufficient time to allow the hydrogenated oils or fats to impregnate the intermediate article, and- recovering the impregnated article and allowing the obtained article comprising the composite material to cool and solidify.

10. The method according to claim 9, wherein said step of drying is selected from: a) drying in drying press mould, and b) drying in convection oven or a microwave dryer.

11. The method according to claim 8 or 9, wherein said bath of melted hydrogenated oils or fats is at a temperature in the range of 50°C to 190°C.

12. The method according to any of claims 9 to 11 , wherein said submerging is maintained for a period of time in the range of 1 to 20 seconds and preferably in the range of 2 to 20 seconds.

13. The use of the composite material of any one of claims 1 to 7, in an application selected from paper-based bottle, cartons, trays, packaging material, furniture, furniture inserts, construction, burial coffins, and art and crafts.

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