阅读说明：本技术 烟草烟雾过滤器 (Tobacco smoke filter ) 是由 A.D.麦科马克 M.J.蒂珀 S.J.鲁塞尔 V.切蒂 于 2013-02-25 设计创作，主要内容包括：本发明涉及烟草烟雾过滤器。一种包括非织造织物的烟草烟雾过滤器或过滤器元件,其中非织造织物包含：短纤维片；和水溶性粘合剂,其中水溶性粘合剂均匀涂在短纤维片的至少一个面上。过滤器具有优良的生物降解性。(The present invention relates to tobacco smoke filters. A tobacco smoke filter or filter element comprising a non-woven fabric, wherein the non-woven fabric comprises: a short fiber sheet; and a water-soluble binder, wherein the water-soluble binder is uniformly coated on at least one side of the short fiber sheet. The filter has excellent biodegradability.)

1. A tobacco smoke filter or filter element comprising a non-woven fabric, wherein the non-woven fabric comprises: a short fiber sheet; and a water-soluble binder, wherein the nonwoven fabric is a wet-laid nonwoven fabric, and wherein the water-soluble binder is uniformly coated on at least one side of the staple sheet prior to subsequent drying; and wherein the staple fibers have a "rapid biodegradability" rating of biodegradability as determined according to OECD 301B "rapid biodegradability" method (modified Sturm test).

2. The tobacco smoke filter or filter element of claim 1 wherein the nonwoven fabric further comprises wood pulp.

3. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the staple fibres are staple fibres cut to a length of 4mm to 10 mm; and/or wherein the staple fibers are staple fibers having a diameter of 1.7dtex to 3.3 dtex.

4. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the staple fibres are staple fibres cut to a length of 4 to 6 mm; and/or wherein the staple fibers are staple fibers having a diameter of 1.7dtex to 3.3 dtex.

5. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the staple fibres are regenerated cellulose fibres, viscose fibres, lyocell fibres, polyvinyl alcohol, polylactic acid, polyglycolic acid or cotton.

6. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the amount of binder is from 0.1% to 5%, expressed as a percentage of the solids content of the finished nonwoven fabric.

7. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the water soluble binder is carboxymethyl cellulose, polyvinyl alcohol, hydroxy cellulose, polyethylene oxide, natural or modified starch, cationic starch, guar gum or a derivative thereof.

8. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the nonwoven web has a basis weight of from 25 to 42 gsm.

9. A tobacco smoke filter or filter element according to claim 1 or 2 wherein the nonwoven web has a basis weight of from 27 to 40 gsm.

10. A tobacco smoke filter or filter element according to claim 1 or 2 further comprising a flavouring additive; and/or wherein the non-woven fabric is a tobacco smoke filtering material.

11. The tobacco smoke filter or filter element of claim 1 or 2 having dispersibility wherein 95% or more of the nonwoven fabric passes through a 6.3mm pore size screen after being subjected to an EDANA Standard FG511.1 Tier 1 dispersibility shake flask test (using 1.6, 3.15, 6.3 and 12.5mm pore size screens); and/or wherein the nonwoven further comprises wood pulp in an amount of up to 20% by weight of the nonwoven and the amount of binder is from 0.1 to 5%, expressed as a percentage of the solids content in the finished nonwoven.

12. The tobacco smoke filter or filter element of claim 1 or 2 having dispersibility wherein 96% or more of the nonwoven fabric passes through a 6.3mm pore size screen after being subjected to an EDANA Standard FG511.1 Tier 1 dispersibility shake flask test (using 1.6, 3.15, 6.3 and 12.5mm pore size screens); and/or wherein the nonwoven further comprises wood pulp in an amount of up to 20% by weight of the nonwoven and the amount of binder is from 0.1 to 5%, expressed as a percentage of the solids content in the finished nonwoven.

13. A tobacco smoke filter or filter element comprising a non-woven fabric, wherein the non-woven fabric comprises: a short fiber sheet; wood pulp; and a water-soluble binder; wherein the nonwoven fabric is a wet laid nonwoven fabric and wherein prior to subsequent drying, the water soluble binder is uniformly coated on at least one side of the staple sheet and wherein at most 9.5% by weight of the nonwoven fabric is wood pulp.

14. A tobacco smoke filter or filter element comprising a non-woven fabric, wherein the non-woven fabric comprises: a short fiber sheet; wood pulp; and a water-soluble binder; wherein the nonwoven fabric is a wet laid nonwoven fabric and wherein a water soluble binder is uniformly coated on at least one side of the staple sheet prior to subsequent drying, wherein the nonwoven fabric comprises wood pulp in an amount of up to 20% by weight of the nonwoven fabric and the amount of binder is from 0.1 to 5%, expressed as a percentage of the solids content in the finished nonwoven fabric.

15. A nonwoven fabric, wherein the nonwoven fabric comprises: a short fiber sheet; and a water-soluble binder; wherein the nonwoven fabric is a wet laid nonwoven fabric and wherein the water soluble binder is uniformly coated on at least one side of the staple sheet prior to subsequent drying; wherein the water soluble binder is applied to the staple fibers in aqueous form; and wherein said staple fibers have a "rapid biodegradability" rating of biodegradability as determined according to the OECD 301B "rapid biodegradability" method (modified Sturm test).

Technical Field

The present invention relates to filters and filter elements for smoking articles (e.g., cigarettes).

Background

There is a general need to reduce the problems associated with the environmental impact of cigarette butt waste. Most current cigarette filters are constructed from conventional cellulose acetate tow and, therefore, have a slow rate of biodegradation. This creates a problem when the butts are thrown on the ground, so that the filter may be visibly identifiable for a long time. In addition, current cellulose acetate filters do not disperse when thrown into waterways, retaining their characteristic size and shape even after prolonged immersion in water. This creates a problem in wastewater treatment plants where used butts must be removed from the water stream during the treatment process. Of course, many butts that are initially thrown to the ground will eventually end up in a water treatment plant after they have been flushed away with the rain drain. Therefore, there is a need for cigarette filters made of readily biodegradable materials and which disperse rapidly when immersed in water. In addition, the filter material must meet a number of other criteria, particularly in a form suitable for high speed conversion into cigarette filters; provide suitable characteristics to the finished filter (e.g., filtration efficiency, hardness, lack of variability, etc.); is economically feasible; and can have acceptable subjective characteristics (especially taste and appearance) in the final cigarette.

This is not a new problem and researchers have been working for decades to find suitable biodegradable cigarette filter materials. During this time a number of patent applications were filed that were claimed to address these needs, but to date have not received any significant market acceptance. Thus, there remains a need for a tobacco smoke filtering material that is readily biodegradable so as to decompose quickly when immersed in water.

Disclosure of Invention

According to the present invention, in a first aspect, there is provided a tobacco smoke filter or filter element comprising a non-woven fabric, wherein the non-woven fabric comprises: a short fiber sheet; and a water-soluble binder, wherein the water-soluble binder is uniformly coated on at least one side of the short fiber sheet.

According to the present invention, in another aspect, there is provided a tobacco smoke filter or filter element comprising a nonwoven fabric, wherein the nonwoven fabric comprises: staple fibers (e.g., staple fiber sheets); and a water-soluble binder, wherein the water-soluble binder is applied to the staple fibers in aqueous form.

Drawings

Figure 1 shows a graph of the biodegradability of the "Viscose 2" and "Tencel 2" filter rods of the present invention as a function of time, compared to known cellulose acetate filter rods "CA".

Detailed description of the preferred embodiments

A nonwoven fabric may be defined as a sheet or web structure in which fibers or filaments are entangled together (and through a perforated film) by mechanical, thermal, or chemical means. They can be made directly from separate fibers (or from molten plastic or plastic film). The term "nonwoven" expressly excludes paper or base paper herein.

Preferably the nonwoven fabric is a wet laid nonwoven fabric. The nonwoven fabric may have a basis weight of 25 to 42gsm, for example 27 to 40 gsm.

The staple fibers are preferably biodegradable materials. The staple fibers may be regenerated cellulose fibers such as Viscose (Viscose) or Tencel (Tencel), both available from Lenzing AG. Other biodegradable fibers, such as polyvinyl alcohol (PVOH), polylactic acid (PLA), polyglycolic acid (PGA), or cotton, may also be used. Poorly biodegradable or non-biodegradable fibers, such as cellulose acetate fibers, cellulose ester fibers, may be used, but these are not preferred. Preferably, the staple fibers are not cellulose acetate fibers or cellulose ester fibers.

Preferably, the filter/filter element and/or the nonwoven fabric and/or staple fiber has a "fast Biodegradability" rating of Biodegradability as determined according to OECD 301B "fast Biodegradability" method (modified Sturm test), as is well known in the art.

The staple fibres may be staple fibres having a cut length of 4mm to 10mm, for example 4 to 6 mm. The staple fibers may have a diameter of 1.7dtex to 3.3 dtex. The staple fibers can be of any cross-section (e.g., round, trilobal, etc.). It is understood that staple fibers of any cut length and diameter suitable for use in a wet laid nonwoven fabric may be used without departing from the spirit of the invention, and that mixtures of different fibers, fiber lengths or fiber diameters may be used in the fabric.

The amount of water-soluble binder may be from 0.1% to 5%, for example from 0.5 to 3%, for example 1%, expressed as a percentage of the solids content in the finished nonwoven fabric. The water-soluble binder may be carboxymethyl cellulose (CMC), polyvinyl alcohol (PVOH), hydroxy cellulose, polyethylene oxide, natural starch, modified starch, cationic starch, guar gum, or derivatives of the foregoing. The adhesive may be applied by any known method suitable for applying liquid adhesives, for example, curtain coating, size press, mangle padding, spray coating, and the like. Preferably the nonwoven fabric does not comprise a basic compound.

The filters and elements of the present invention comprise a nonwoven fabric comprising (e.g., chopped biodegradable) staple fibers (e.g., regenerated cellulose fibers) and a water-soluble binder. Preferably the water soluble binder is applied in aqueous form (to the fibres). Preferably the water soluble binder is applied in aqueous form (to the fibres) and subsequently dried.

The specific nonwoven material is preferably made by a wet laid process. Nonwoven fabrics can be prepared by a variety of different well-known manufacturing routes (e.g., dry-laid or "carded", spunbond, wet-laid, air-laid, etc.). The applicant has found that wet laid fabrics are best suited to meet the required mouth-to-mouth (tip-tip) pressure drop reproducibility criteria required for cigarette filters, a critical prerequisite for a viable tobacco smoke filtration material (irrespective of its dispersibility). The pressure drop relates to the weight of the fabric used per nozzle. The basis weights of the paper and nonwoven were measured using standard methods that quantify the weight of at least 20 x 25cm area. The amounts used in typical cigarette filters use only about 10% of this amount, and thus data based on the weight variability of such larger test samples may be misleading as to their suitability to meet the reproducibility criteria of cigarette filters. By measuring the weight change rate of a 2cm x 30cm strip of fabric, applicants determined that a wet laid nonwoven is most suitable for meeting the desired weight change rate requirement of no more than about ± 1%.

Wet laid fabrics made from 100% staple fibers are extremely weak and do not have sufficient mechanical integrity to withstand handling on filter making machinery. Thus, adhesives are needed to provide sufficient strength to the fabric. Prior art wet laid fabrics typically incorporate thermoplastic binder fibers as part of the fiber furnish, and then activate these binder fibers during the drying stage of fabric manufacture. However, applicants have found that fabrics incorporating binder fibers are not suitable for use in the present application because they do not readily disperse in cold water (see comparative example 3 below). Applicants have found that the result of using a (e.g. liquid) water soluble binder in combination with the short fibers can enable rapid dispersion in cold water.

The nonwoven fabric may be a fabric having dispersibility wherein 95% or more (e.g., 96% or more) of the nonwoven fabric passes through a 6.3mm pore size screen after passing through an EDANA standard FG511.1 Tier 1 dispersibility Shake Flask Test (using 1.6, 3.15, 6.3, and 12.5mm pore size screens). This test is well known in the art and this dispersibility means an easy and effective dispersion in cold water (high dispersibility).

The final appearance and hardness of the filters of the invention are also similar to cellulose acetate filters, again improving their commercial acceptability.

Advantageously, the nonwoven fabric used in the filter of the present invention may be processed (e.g., molded) using standard equipment used in the manufacture of paper-based cigarette filters. The paper filter gave greater tar retention than the cellulose acetate filter with the same pressure drop. This means that it is not possible for cigarette manufacturers to simply replace cellulose acetate filters with paper filters because the length of the filter needs to be changed (to maintain the same pressure drop or tar delivery) or the cigarette tar delivery is reduced and the pressure drop is increased (for a constant filter length). Applicants have found that the tar retention of the filters and filter elements of the present invention is very close to cellulose acetate, rather than paper. Applicants have also found that the more open and inherently porous the fabric structure, the lower the tar retention of a filter incorporating that material. Thus, the porosity of the nonwoven fabric can be engineered to provide desirable tar retention and pressure drop filters and filter elements by controlling the constituent fiber properties, such as polymer type, fiber cross-section, fiber crimp and fiber size. This means that the filters/elements of the present invention are more advantageous because they can be used as a simple replacement for cellulose acetate filters.

The nonwoven fabric may further comprise wood pulp. The term "wood pulp" as used herein includes pulp comprising naturally occurring cellulosic fibers (e.g., obtained from softwood or hardwood by conventional methods, such as the sulfite or Kraft processes), which may have been beaten (as is well known in the art), for example, using conventional beaters or refiners. Wood pulp can increase the tensile strength of the nonwoven fabric. If wood pulp is included, it is preferably present in an amount of 0.1 to 20% by weight, for example 5 to 10% by weight, based on the weight of the nonwoven fabric. In a preferred example, wood pulp is included in an amount of up to 9.5% by weight, such as 1 to 9%, for example 5 to 9% by weight of the nonwoven fabric. Applicants have surprisingly found that nonwoven fabrics comprising such relatively small amounts of wood pulp (plus water-soluble binder) are strong enough to form filter/filter elements. In a different preferred example, wood pulp is included in an amount of up to 20% by weight, for example 1 to 20% by weight, of the weight of the nonwoven fabric, and the water-soluble binder is present in an amount of 0.1% to 5%, expressed as a percentage of the solids content in the finished nonwoven fabric.

Thus, according to the present invention, in one aspect, there is provided a tobacco smoke filter or filter element comprising a nonwoven fabric, wherein the nonwoven fabric comprises: a short fiber sheet; wood pulp; and a water-soluble binder, wherein the water-soluble binder is uniformly coated on at least one side of the staple sheet, and wherein at most 9.5% by weight of the nonwoven fabric is wood pulp.

According to the present invention, in another aspect, there is provided a tobacco smoke filter or filter element comprising a nonwoven fabric, wherein the nonwoven fabric comprises: a short fiber sheet; wood pulp; and a water-soluble binder, wherein the water-soluble binder is uniformly coated on at least one side of the staple sheet, wherein the nonwoven fabric comprises wood pulp in an amount of up to 20% by weight of the nonwoven fabric, and the amount of the binder is from 0.1 to 5%, expressed as a percentage of the solids content in the finished nonwoven fabric. Preferably, the staple fibers are not cellulose acetate fibers or cellulose ester fibers.

The tobacco smoke filter or filter element may further comprise a flavouring additive. The flavouring additive may be an additive for a paper filter as disclosed in WO 2010/136751. The flavour enhancing additive may be an alicyclic lactone, an aromatic ketone or secondary alcohol or ester thereof, phthalide, chi-valerolactone, chi-caprolactone, delta-caprolactone, chi-heptolactone, chi-octalactone, delta-octalactone, 4-hydroxy-3-pentenoate lactone, 5-hydroxy-2-decenoic acid delta-lactone, 4-dibutyl-chi-butyrolactone, mentholactone, dehydromenthofuranlactone, 3-butylidenephthalide, 3-n-butylphthalide, whiskey lactone or celerianiside (sedanenolide).

The tobacco smoke filter or filter element may comprise a longitudinally extending core of tobacco smoke filtering material. The tobacco smoke filtering material may comprise or may be a non-woven fabric. The longitudinally extending core of tobacco smoke filtering material may be substantially cylindrical.

The tobacco smoke filter or filter element of the invention may have a circumference of 14 to 28mm, for example 16 to 26mm, for example 16 to 17mm or 24 to 25 mm. The tobacco smoke filter of the present invention may be 10 to 40mm long, for example 15 to 35mm, for example 20 to 30 mm. The tobacco smoke filter element of the invention may be 5 to 30mm long, for example 6 to 20mm, for example 8 to 15mm, for example 10 to 12 mm.

The tobacco smoke filter or filter element of the present invention may further comprise a wrapper (wrapper), for example a tipping paper (plugwrap). The wrapper is preferably engaged around the tobacco smoke filter or filter element (e.g. around the longitudinally extending core of tobacco smoke filtering material). The wrapper (e.g., tipping paper) is preferably held in place with a water soluble adhesive (e.g., by a lap tack seam, as is known in the art). The water-soluble binder advantageously facilitates opening of the filter upon contact with water to expose the filter material (nonwoven fabric) contained therein, thereby facilitating destruction of the filter (nonwoven fabric) after use.

The filter or filter element of the present invention may be used as a single filter, as a filter rod, as one or more segments within a multi-segment filter, and the like. Thus, the filter elements of the present invention may be used as segments of a dual, triple, or other multi-component (multi-segment) filter. Dual component and other multi-component filters are known in the art. The filters of the present invention may be used for machined cigarettes (e.g., those produced and packaged in bulk). The filters of the present invention may also be used as filters for personal cigarette (e.g., hand cigarette) or roll Your Own or Make-Your-Own products.

According to the present invention, in another aspect, there is provided a filter cigarette comprising the tobacco smoke filter or filter element of the present invention. In the filter cigarette of the invention, the filter of the invention (or a filter comprising the filter element of the invention) is attached to the wrapped tobacco rod with one end facing the tobacco. The filter may be joined to the wrapped tobacco rod, for example, by loop wrapping (joining just around the adjacent ends of the [ wrap ] filter and rod to leave much of the filter wrapper exposed), or by over wrapping paper (over wrap) (joining around the full filter length and the adjacent end of the tobacco rod). Preferably the tipping paper/wrapper and/or the tipping paper comprises a water soluble lap adhesive. The water-soluble binder advantageously facilitates opening of the filter upon contact with water to expose the filter material (nonwoven fabric) contained therein, thereby facilitating destruction of the filter (nonwoven fabric) after use.

Any filter or filter cigarette of the present invention may be unperforated or may be apertured by methods well known in the art, for example, using pre-perforated or air-permeable tipping paper, and/or laser perforating the tipping paper and tipping overwrap.

The filter or filter element of the present invention can be made as a continuous rod (by methods known in the art). Upon continuously exiting the maker outlet, the continuous rod is cut to a defined length for subsequent use. This cutting may form individual filters or filter elements as defined and described above, which are then separately attached to each wrapped tobacco rod to form a filter cigarette. More typically, however, the continuous exiting filter rod is first cut to double or more (typically four or six times) the length for subsequent use; upon initial cutting to four or more times the length, the latter is subsequently cut to double length for filter cigarette assembly, wherein double length filter rods are assembled and joined (by tipping in loops or tipping in full tipping overwrap) between a pair of wrapped tobacco rods, and then combined at the center to give two separate filter cigarettes. Similar techniques are used to combine, for example, double length filter elements that produce double or multiple filters, as is known in the art. The present invention includes double and higher length filter rods (and/or filter element rods).

According to the present invention, in another aspect, there is provided a nonwoven fabric, wherein the nonwoven fabric comprises: a short fiber sheet; and a water-soluble binder, wherein the water-soluble binder is uniformly coated on at least one side of the short fiber sheet. According to the present invention, in another aspect, there is provided a nonwoven fabric, wherein the nonwoven fabric comprises: staple fibers (e.g., staple fiber sheets); and a water-soluble binder, wherein the water-soluble binder is applied to the staple fibers in aqueous form. Preferably the nonwoven fabric is a wet laid nonwoven fabric. The nonwoven fabric of the present invention includes (e.g., chopped biodegradable) staple fibers and a water-soluble binder. Preferably the water soluble binder is applied in aqueous form (to the fibres). The staple fibres may be staple fibres having a cut length of 4mm to 10mm, for example 4 to 6 mm. The staple fibers may have a diameter of 1.7dtex to 3.3 dtex. The staple fibers can be of any cross-section (e.g., round, trilobal, etc.). It is understood that staple fibers of any cut length and diameter suitable for use in a wet laid nonwoven fabric may be used without departing from the spirit of the invention, and that blends of different fibers, fiber lengths or fiber diameters may be used in the fabric.

The staple fibers are preferably biodegradable materials. The staple fibers may be regenerated cellulose fibers, such as viscose or lyocell, both available from Lenzing AG. Other biodegradable fibers, such as polyvinyl alcohol (PVOH), polylactic acid (PLA), polyglycolic acid (PGA), or cotton, may also be used. Poorly biodegradable or non-biodegradable cellulose acetate fibers may be used, but these are not preferred.

The nonwoven fabric may further comprise wood pulp. Wood pulp can increase the tensile strength of the nonwoven fabric. If wood pulp is included, it is preferably present in an amount of 0.1 to 20% by weight, for example 5 to 10% by weight, based on the weight of the nonwoven fabric.

The amount of water-soluble binder may be from 0.1% to 5%, for example from 0.5 to 3%, for example 1%, expressed as a percentage of the solids content in the finished nonwoven fabric. The water-soluble binder may be carboxymethyl cellulose (CMC), polyvinyl alcohol (PVOH), hydroxy cellulose, polyethylene oxide, or starch. The adhesive may be applied by any known method suitable for applying liquid adhesives, for example, curtain coating, size press, pad mangle, and the like. Preferably the nonwoven fabric does not comprise a basic compound.

In a preferred example, wood pulp is included in an amount of up to 9.5% by weight of the nonwoven fabric, such as from 1 to 9%, such as from 5 to 9%. Applicants have surprisingly found that nonwoven fabrics having such relatively low amounts of wood pulp (in addition to water soluble binders) are strong enough to form filter/filter elements. In a different preferred example, wood pulp is included in an amount of up to 20% by weight of the nonwoven, for example 1 to 20%, and the water-soluble binder is present in an amount of 0.1% to 5%, expressed as a percentage of the solids content in the finished nonwoven.

Preferably, the staple fibers are not cellulose acetate fibers or cellulose ester fibers.

According to the present invention, in another aspect, there is provided a tobacco smoke filter or filter element comprising a filtration material comprising a nonwoven fabric of the present invention.

The invention will now be illustrated with reference to the following examples and figures, in which figure 1 shows a graph of the biodegradability of the "Viscose 2" and "Tencel 2" filter rods of the invention as a function of time, in comparison with known cellulose acetate filter rods "CA".