CN116601358A - Softener concentrate, softener emulsion, method for producing softener emulsion and use thereof - Google Patents

Abstract

The present invention provides softener concentrates and softener emulsions comprising imidazoline-based surfactants, lanolin-based softeners, phospholipids and surfactant blends. The invention further provides a method for producing the softener emulsion and controlling the viscosity of the softener emulsion. The invention also provides a method for producing paper, tissue or board, in which method the softener according to the invention is used.

Description

Softener concentrate, softener emulsion, method for producing softener emulsion and same use

technical field

The present invention relates to softener concentrates and softener emulsions. The present invention further relates to methods for producing softener emulsions and controlling the viscosity of softener emulsions. The invention also relates to a method for producing paper, tissue or board, in which method the softening agent according to the invention is used.

Background technique

Softeners are commonly used to impart body in, for example, facial tissue and textile products by reducing the number of interfiber hydrogen bonds and by the presence of emollient chemicals on the facial tissue or textile surface to improve surface softness and smoothness Softness (bulk softness). Conventionally, softener emulsions consist mainly of imidazoline-based surfactants, which may pose health hazards as well as environmental risks. Therefore, there is a need for tissue and textile products that can be more environmentally friendly and at the same time provide satisfactory softness. These products should also meet consumer expectations for sustainability and eco-friendliness.

Another disadvantage of conventional softener emulsions is high viscosity. The viscosity of an emollient emulsion can rapidly increase to a range from 500 to 10,000 cPs during emulsification, making application of the emulsion difficult or even impossible. In spray applications, especially dry sheet spray applications, it is desirable to use low viscosity softener emulsions with viscosities below 500 cPs, preferably below 100 cPs. Dilution of higher viscosity emulsions with water to reduce viscosity may not be a viable option, as dilution may destabilize the emulsion, leading to clogging of the sprayer. Furthermore, diluting the softener emulsion results in a greater amount of water being sprayed onto the dried sheet, resulting in a breakdown of the integrity of the sheet in the paper product.

Another problem associated with high viscosity is that entrained air introduced during mixing or homogenization cannot be easily released. Entrained air in the emulsion can cause emulsion instability, promote microbial growth, and promote undesired oxidation. Therefore, there is a need for effective methods of reducing the viscosity of such softener emulsions.

One possible explanation for the high viscosity of the softener emulsion is the bubble bridge phenomenon created by the entrained air. The surfactant molecules in the softener emulsion help to form entrapped air bubbles during agitation or homogenization and make the air bubbles a very stable structure, preventing coalescence to form larger air bubbles that will rise and release to the environment. Entrained air bubbles can form bridges with particles in the emulsion, and this phenomenon leads to increased bonding between particles and in turn to an increase in bulk viscosity.

Contents of the invention

The object of the invention is to minimize or possibly even eliminate the disadvantages of the prior art.

Another object of the present invention is to provide an improved softener product which results in higher softness in paper, tissue or board products.

Another object of the present invention is to provide environmentally friendly bio-based softener products with reduced health risks compared to imidazoline-based softener products present in the prior art.

These objects are achieved by the invention having the features presented below in the characterizing parts of the independent claims. Some preferred embodiments are disclosed in the dependent claims.

The features recited in the dependent claims and the embodiments in the description are mutually freely combinable unless otherwise explicitly stated.

The exemplary embodiments and their advantages provided herein relate to all aspects of the invention by applicable parts, even if this is not always explicitly mentioned.

Typical softener concentrates for making paper, tissue or board according to the invention include

- 5% to 10% by weight of the total weight of the softener concentrate of imidazoline-based surfactants having a carbon chain longer than 10 carbon atoms;

- softeners based on lanolin;

- phospholipids; and

- Surfactant blends comprising polysorbates, sorbitan ester-based surfactants, polypropylene glycol, polyethylene glycol, and their esters, silicon-based softeners, or any combination thereof.

The inventors have surprisingly found that by using softener concentrates according to the invention it is possible to reduce the imidazoline content of softener products while still providing similar performance as when using conventional softeners with higher imidazoline concentrations. Thus, the present invention has the advantage of minimizing the health hazards posed by imidazoline-based surfactants and also provides bio-based softener products that are less harmful to the environment. The softener concentrates of the present invention are well suited for oil-in-water emulsifiers having a Hydrophile-Lipophile Balance (HLB) value of 8-9.

It has now surprisingly been found that lanolin-based softeners and phospholipids are very suitable for use in softener products. Lanolin-based emollients and phospholipids such as lecithin provide bio-based alternatives to conventional imidazoline-based surfactants. Lanolin-based emollients and phospholipids are mostly digestible, which makes them very safe materials for surfactant production.

A typical softener emulsion according to the invention comprises:

- 20 to 50 wt-%, preferably 25 to 30 wt-%, of the total weight of the softener emulsion of this softener concentrate, comprising

- 5% to 10% by weight of the total weight of the softener concentrate of imidazoline-based surfactants having a carbon chain longer than 10 carbon atoms;

- softeners based on lanolin;

- phospholipids;

-surfactant blends comprising polysorbates, sorbitan ester-based surfactants, polypropylene glycol, polyethylene glycol, and their esters, silicon-based softeners, or any combination thereof,

as well as

- total weight of softener emulsion 50 wt-% to 80 wt-%, preferably 70 wt-% to 75 wt-%, water.

The present inventors have surprisingly found that the softener emulsions of the present invention produce improved softness in paper, facial tissue, paperboard compared to conventional softeners.

Typical methods for producing the softener emulsions of the present invention include:

-Provide a softener concentrate which contains

- 5% to 10% by weight of the total weight of the softener concentrate of imidazoline-based surfactants having a carbon chain longer than 10 carbon atoms;

- softeners based on lanolin;

- phospholipids;

-surfactant blends comprising polysorbates, sorbitan ester-based surfactants, polypropylene glycol, polyethylene glycol, and their esters, silicon-based softeners, or any combination thereof,

- emulsifying the softener concentrate with water, thereby forming a softener emulsion comprising 20 wt-% to 50 wt-% of the softener concentrate relative to the total weight of the softener emulsion,

- Treating the softener emulsion with a high shear homogenizer and/or ultrasonic energy to reduce the viscosity of the softener emulsion.

The present invention has the advantage of providing a method for effectively and cost effectively reducing the viscosity of softener emulsions. According to the invention, the viscosity of the softener emulsion can be reduced directly after the emulsification step and/or after transport to the production site where the softener emulsion is used.

The present inventors have surprisingly found that the use of a high shear homogenizer as a post-treatment of softener emulsions breaks the bubble bridges and releases entrapped air, resulting in a lower bulk viscosity. Homogenization provides the combined effect of three main phenomena, including shear, turbulence and cavitation.

The inventors have surprisingly found that sonication can be used to reduce the viscosity of the softener emulsions according to the invention. This creates high shear forces that can break both intermolecular and intramolecular bonds, leading to the breakdown of aggregates in the softener emulsion, which in turn reduces the viscosity of the emulsion. Additionally, sonication can be used to degas liquids. Ultrasonic cavitation can generate shear forces that can break up aggregates, thereby reducing particle size and viscosity. In addition, ultrasonic energy can create vacuum voids in the emulsion, and thus microbubbles migrate into the voids, resulting in an increase in the size of the bubbles and the release of entrained air to the environment. This can also lead to the breakdown of the air bridges and thus to a decrease in viscosity.

High shear homogenization and sonication can be used alone or in combination as a post-treatment of the emulsion. Furthermore, both methods can be operated directly at the production site, using a sprayer system to spray and apply the softener emulsion. The viscosity of softener emulsions tends to increase during shipping, even if the emulsion is treated with a high shear homogenizer and/or sonicated shortly after preparation. The invention has the advantage of providing a softener emulsion which has a new reduced viscosity directly at the production site where it is used.

The present invention can also be used as a treatment to reduce the viscosity of the softener emulsion prior to filtration to remove any undissolved particles from the emulsion.

The present invention provides a process for the manufacture of paper wherein a softener emulsion is added to a fiber stock having a consistency of 0.05% to 8% by weight at the wet end of a paper, board or tissue machine, and/or the softener emulsion Applying to a wet web having a moisture content of 30% to 90% by weight of water in the wet web and/or applying a softener emulsion to the drying sheet or converting roll Above, the dry sheet or converted roll has a moisture content of less than 12% based on the weight percent of water in the dry sheet or converted roll.

The invention further provides softener emulsions as debonders to produce fluff pulp, as releasing agents in papermaking processes, as bulking agents for tissue, paper and board products, or Use as a fluting agent for linerboard applications. The softener emulsions of the present invention can also be used to increase the bulk and softness of textile products.

Description of drawings

Figure 1 is a schematic diagram of a process for in situ viscosity reduction of softener emulsions for dry sheet spray application,

Figure 2 Dry tensile measurement results for spray application of the dry sheet in Example 2,

Figure 3 Result of softness HF measurement of dry sheet spray application in Example 2,

Softness TS7 measurement results of dry sheet spray application in Figure 4 Example 2,

Softness TS750 measurement results of dry sheet spray application in Figure 5 Example 2,

The softness D value result of dry sheet material spray application in Fig. 6 embodiment 2,

Figure 7 Dry tensile measurements of wet web spray application in Example 3,

Bulk measurement results for wet web spray application in Figure 8 Example 3,

Softness TS7 measurement results of wet web spray application in Figure 9 Example 3,

Softness D value result of wet web spray application among Fig. 10 embodiment 3,

Figure 11 Dry tensile measurement results for wet end application in Example 4,

Figure 12 Loft measurements for wet end application in Example 4,

Figure 13 Softness TS7 measurement results for wet end application in Example 4,

Softness TS750 measurement results for wet end application in Figure 14 Example 4,

Softness D value results for wet end application in Figure 15 Example 4, and

Figure 16 Viscosity change of softener emulsion during sonication in Example 6.

Detailed ways

With regard to a first aspect of the present invention, softener concentrates are disclosed.

In an embodiment of the present invention, the softener concentrate comprises 5 wt% to 10 wt% of an imidazoline-based surfactant having a carbon chain longer than 10 carbon atoms, 5 wt% to 10 wt% lanolin based softener, 5 wt% to 20 wt% phospholipid, and 60 wt% to 85 wt% surfactant blend. According to the present invention, the surfactant blend comprises polysorbates, sorbitan ester based surfactants, polypropylene glycol, polyethylene glycol, and esters thereof, silicon based softeners, or any combination thereof . In a preferred embodiment of the invention, the surfactant blend comprises a sorbitan ester based softener and/or a polysorbate. In an embodiment of the invention, the surfactant blend comprises sorbitan ester-based softener and polysorbate in a weight ratio of 2:1.

In a preferred embodiment, the softener concentrate comprises 5 wt % to 8 wt % imidazoline based surfactant, 5 wt % to 8 wt % lanolin based softener, 7 wt % to 15 wt % of the total weight of the softener concentrate % phospholipids, and 69 wt% to 83 wt% surfactant blend. In a more preferred embodiment, the softener concentrate comprises 5 wt % imidazoline based surfactant, 5 wt % lanolin based softener, 10 wt % phospholipid and 80 wt % surfactant blend based on the total weight of the softener concentrate thing

With regard to a second aspect of the present invention, there is provided a softener emulsion. The softener emulsion according to the invention comprises: 20 to 50% by weight, preferably 25 to 30% by weight of the softener concentrate of the invention and 50 to 80% by weight, preferably 70 to 75% by weight of water, based on the total weight of the softener emulsion. The softener emulsion is produced by emulsifying the softener concentrate according to the invention with water. The softener concentrates according to the invention are typically prepared using conventional mixers or homogenizers. Emulsions are prepared by adding water. After the emulsification process is complete, stop mixing and transfer the softener emulsion to a storage and/or shipping container.

In an embodiment according to the invention, the imidazoline-based surfactant having a carbon chain longer than 10 carbon atoms includes a carbon chain of 16 to 18 carbon atoms. In an embodiment according to the invention, the carbon chain having 16 to 18 carbon atoms is a saturated or unsaturated fatty acid. In preferred embodiments, the fatty acid is selected from oleic acid, palmitic acid, or combinations thereof. According to an embodiment of the present invention, imidazoline-based surfactants are synthesized by reaction of fatty acids with diethylenetriamine (DETA), followed by cyclization, and quaternization with diethyl sulfate. According to an embodiment of the present invention, the ratio of acid to DETA is preferably in the range of 1:1 to 2:1. The cyclization reaction is preferably completed to an extent of 80% to 95%, and the quaternization reaction is preferably completed to an extent of 90% to 95%.

According to the invention, softener concentrates and softener emulsions comprise lanolin-based softeners. In an embodiment, the lanolin-based softener includes USP grade lanolin, lanolin wax, lanolin oil, or any combination thereof. Lanolin is a wax secreted by the sebaceous glands of wool-bearing animals. Lanolin comprises long-chain waxy esters (approximately 97% by weight) with the remainder being lanolin alcohol, lanolin acid and lanolin hydrocarbons. Typically, lanolin is used in personal care, such as cosmetics, and health care, such as topical liniments. The inventors have now surprisingly found that lanolin is suitable for softener concentrates and softener emulsions according to the invention.

In embodiments, the softener concentrate and the softener emulsion comprise phospholipids. In a preferred embodiment according to the invention, the phospholipids comprise lecithin. Lecithins are a group of fatty substances found in animal and plant tissues. Lecithin is amphiphilic and is known for smoothing food textures, emulsifying, homogenizing liquid mixtures, and repelling adherent materials. In an embodiment according to the invention, the lecithin is derived from soybean, sunflower oil, rapeseed and/or cottonseed. Soy and sunflower oils are the main sources of lecithin. Other related sources of lecithin include rapeseed. According to an embodiment of the present invention, the inventors have found that soy lecithin and/or sunflower lecithin are well suited for softener concentrates and softener emulsions. Therefore, in a preferred embodiment of the present invention, the lecithin comprises soybean lecithin and/or sunflower lecithin.

In an embodiment according to the invention, the softener emulsion further comprises electrolytes. In embodiments of the present invention, the electrolyte may be selected from soluble salts, acids, bases, polyelectrolytes, or any combination thereof. In an embodiment according to the invention, the electrolyte includes NaCl, CaCl ₂ , MgCl ₂ , NaNO ₃ , Na ₂ SO ₄ , KCl, phosphate anions, or any combination thereof. Electrolytes have the advantage of contributing to the viscosity reduction of the softener emulsion.

In an embodiment according to the invention, the softener emulsion comprises electrolytes in an amount of from 0.01 wt% to 1.0 wt%, preferably from 0.01 wt% to 0.5 wt-%, more preferably from 0.01 wt% to 0.3% by weight of the softener emulsion wt % or 0.01 wt % to 0.25 wt % and even more preferably 0.01 wt % to 0.05 wt %. If the electrolyte concentration is too high, the electrolyte can reduce the stability of the softener emulsion. Therefore, the softener composition preferably has a low concentration of electrolytes. Ideally, the electrolyte concentration can be high enough to provide the low desired viscosity while maintaining the stability of the softener emulsion. According to an embodiment of the invention, the electrolyte is added in an amount that reduces the viscosity of the softener emulsion to below 500 cPs, preferably below 200 cPs, more preferably below 100 cPs, even more preferably below 50 cPs (when using a Brookfield viscometer (Brookfield Viscometer) (DV2T) with #63 spindle and spindle speed at 30 rpm when measured at ambient temperature). Emollient emulsions with low viscosity have the advantage of simple and direct application by spraying, with reduced or eliminated risk of clogging the spray system.

With regard to a third aspect of the present invention, there is provided a method for producing a softener emulsion. The production process steps may be performed at a single location, or the softener emulsion may be transported, for example, to a papermaking site prior to the high shear homogenizer and/or ultrasonic treatment steps.

In an embodiment according to the invention, the method for producing a softener emulsion includes adding electrolytes. In an embodiment of the invention, the electrolyte is selected from soluble salts, acids, bases, polyelectrolytes, or any combination thereof. In preferred embodiments, the electrolyte includes NaCl, CaCl ₂ , MgCl ₂ , NaNO ₃ , Na ₂ SO ₄ , KCl, phosphate anions, or any combination thereof. The present inventors have surprisingly found that adding an electrolyte to a softener emulsion advantageously results in a decrease in the viscosity of the softener emulsion.

In an embodiment according to the present invention, the electrolyte is 0.01wt% to 1.0wt%, preferably 0.01wt% to 0.5wt%, more preferably 0.01wt% to 0.3wt%, or 0.01wt% of the weight of the softener emulsion to 0.25 wt%, and even more preferably 0.01 wt% to 0.05 wt%. In an embodiment according to the invention, the electrolyte is added before, during and/or after the emulsification step, preferably after the emulsification step. In another embodiment according to the invention, the electrolyte is added before, during and/or after the high shear homogenizer and/or sonication.

In an embodiment of the invention, this method can also be used as a treatment to reduce the viscosity of the emulsion prior to filtration in order to remove any undissolved particles.

In an embodiment of the invention, the method can also be used as a treatment to reduce the viscosity of the emulsion in order to improve the stability of the emulsion.

High shear homogenizer treatment and/or sonication can be performed at the production site with a sprayer system for spray application of the softener emulsion. The advantage of combining the addition of electrolytes with a high shear homogenizer and/or sonication is the simple processing of the softener emulsion directly on site, achieving a freshly processed softener emulsion with low viscosity, ready for spray application of the pure product.

In an embodiment of the invention, the softener emulsion is treated with ultrasonic energy for 1 to 60 minutes, preferably 10 to 30 minutes. Treating the softener emulsion for a preferred time reduces the viscosity of the softener emulsion to a preferred level.

According to the invention, the softener emulsion can be added to the fiber stock at the wet end of the paper machine and/or can be applied to the wet fiber web or onto the dry sheet or converting rolls. The emulsion can be applied to the wet web and/or dry sheet by spraying or any other suitable method.

In an embodiment, the softener emulsion may be added to the fiber stock at the wet end of the paper, facial tissue or board machine. The fiber stock may comprise bleached and/or unbleached fibers including virgin fibers and/or recycled fibers from the following fiber sources: hardwoods (HW) such as eucalyptus, poplar and birch; softwoods ( SW), such as spruce, pine, fir, larch and/or hemlock; non-wood fibers such as bamboo, cotton, hemp and/or flax, or any combination thereof.

According to an embodiment of the invention, the emulsion may be diluted for wet-end application. The diluted softener emulsion may comprise 0.01 to 10% by weight of the softener concentrate, and 90 to 99.9% by weight of water, preferably the diluted softener emulsion comprises 0.01% by weight of the total weight of the softener emulsion. to 5 wt% softener concentrate and 95 to 99.9 wt% water. In a particularly preferred embodiment, the diluted softener emulsion comprises 1% by weight softener concentrate and 99% water, based on the total weight of the diluted softener emulsion. According to an embodiment of the invention, the dosage of the softener emulsion may be from 1.5 to 20 kg/t (3 to 40 lb/ton) of dry stock by weight of the softener concentrate, preferably from 1.5 to 6 kg/t (3 to 12lb/ton) of dry pulp.

In an embodiment of the invention, a softener emulsion may be applied to a wet web. Emollient emulsions are usually applied by spraying. The web may have a moisture content of 30% to 90%, based on the weight percent of water in the wet web. According to an embodiment of the invention, the dosage of the softener emulsion may be from 1.5 to 20 kg/t (3 to 40 lb/ton) of dry stock by weight of the softener concentrate, preferably from 1.5 to 6 kg/t (3 to 12lb/ton) of dry pulp.

In an embodiment of the invention, the softener emulsion can be applied to a dry sheet or to a transfer roll. The dried sheet or converted roll may have a moisture content of less than 12% based on the weight percent of water in the dried sheet or converted roll. According to an embodiment of the invention, the dosage of the softener emulsion may be from 1.5 to 20 kg/t (3 to 40 lb/ton) dry stock, preferably from 1.5 to 6 kg/t (3 to 12 lb/ton) dry stock , as the weight of softener concentrate.

In this disclosure, t refers to tons (1000 kg) and ton refers to short tons (2000 lb).

Spraying the softener onto the dry sheet requires a low viscosity fluid to achieve a uniform spray pattern. For example, one of the industry standard equipment, the WEKO fluid application system, prefers softener emulsions with viscosities even below 100 cPs. Although the viscosity of a softener emulsion may decrease immediately after manufacture, during transportation or storage at high or cold temperatures, the viscosity may increase because the particles tend to agglomerate. Therefore, there is a need for an on-site method of reducing emulsion viscosity and maintaining low emulsion viscosity.

Figure 1 depicts a new method using a high shear homogenizer device or ultrasonic unit with or without added electrolyte to achieve low viscosity. The softener emulsion can be stored in storage tank 1 . The softener emulsion is pumped through a high shear or ultrasonic device in unit 2. A high shear homogenizer can be any high speed machine that provides homogenization, emulsification or disintegration, such as a homogenizer, colloid mill or emulsifier. A desired amount of electrolyte can be added on (A) the top of the storage tank 1 or (B) the inlet of the discharge pump of the storage tank 1 . The softener emulsion can be recycled (C) to tank 1 until the viscosity of the emulsion reaches the target range. Subsequently, the emulsion can be supplied to the dry sheet spray system 3 .

The present invention further provides the use of the softener emulsion for increasing the bulk and softness of textile products. Containing cationic surfactants, the softener emulsions according to the invention adhere well to natural fibers such as wool and cotton. The softener emulsions according to the present invention provide a bio-based alternative to synthetic fabric softeners.

The present invention further provides the use of the softener emulsion as a debonding agent for the production of fluff pulp. Fluff pulp is used, for example, in baby diapers, feminine hygiene products and sanitary napkins. Fluff pulp products are typically converted from sheet form to individual fibers. The pulp is usually treated at the wet end with a debonding agent which can interfere with the formation of hydrogen bonds between the fibers during drying. The softener emulsion according to the invention is very suitable as a debonding agent to defibrillate the pulp by controlling the hydrogen bonds between the fibres.

The present invention further provides the use of the softener emulsion as a release agent in the manufacture of paper and board. The softener emulsions according to the invention can provide bio-based alternatives to conventional mold release agents with good mold release properties.

The present invention further provides the use of the softener emulsion as a bulking agent for facial tissue, paper and board products. Bulking agents increase the pore volume of the tissue, paper or paperboard product, resulting in an increase in sheet thickness. Emulsions of softeners according to the invention can provide a biobased alternative to conventional bulking agents.

The present invention further provides the use of a softener emulsion as a channeling agent for linerboard applications.

experiment

Experiment 1. Handsheet Preparation for Softener Wet End Application

Two different fiber blends, 50:50 and 70:30 eucalyptus to cork ratios, were used in this evaluation. The eucalyptus pulp was repulped with a Valley beater without refining. Laboratory cork was refined to approximately 500 CSF (Canadian Standard Freeness) and blended with eucalyptus at target ratios. The fiber blend was diluted with synthetic water treated with 35 ppm Ca2 ⁺ and 150 ^ppm _SO42- each to about 0.45%. The pH of the furnish was about 7.0.

The chemicals were mixed with the fiber slurry for 45 seconds prior to making the handsheets. The softener emulsion was diluted to a softener concentrate concentration of 1% by weight of the total weight of the diluted softener emulsion, then at 3 and 6 kg/t dry stock (6 and 12 lb/t dry paper) (by weight of softener concentrate) Measure into the thinning ingredients. In some examples, a commercial coagulant (FennoFix501, Kemira Oyj) was used.

Handsheets were produced by means of a Dynamic SheetFormer (DSF) from Techpap according to a standard handsheet protocol (target to about 35 g/m ² ). Sheets were roller dried (60 seconds total dry time set at 115° C.) with a backed blotter paper without wet pressing.

Experiment 2. Handsheet Preparation for Wet Web Spray of Softener Emulsion

Thin batches were prepared analogously to Experiment 1. Two blank conditions were included in the wet web study. No chemicals are added at the wet end. Handsheets were produced according to a standard handsheet protocol (target to about 35 g/m ² ) by a dynamic sheet former (DSF) from Techpap. After making the handsheets, the mother paper was cut into 3 pieces with a width of 23 cm (9 inches). Each monolith was sprayed using a 1550 AutoJet Modelar spray system with a Phoenix I single axis Servo controller. Dosage of softener was 3 and 6 kg/t dry stock (6 and 12 lb/t dry stock). The sheet was then sandwiched between two sheets of blotter paper and tumble dried without wet pressing (60 seconds total drying time set at 115°C).

Experiment 3. Dry flake spray of softener emulsion

The sheet used for the dry sheet spray was a commercial bath towel base sheet from a facial tissue mill. The base sheet has a basis weight of about 20 g/m ² . The spray system was a 1550 AutoJet Modular spray system with a Phoenix I single axis Servo controller. A 30% softener emulsion was used for this study. Addition rates were estimated by the difference in sheet weight before and after spraying, then dividing by the sheet weight. After spraying, the sheet was dried for 60 seconds without applying pressure using a heat press set at 121°C (250°F).

Experiment 4. Paper sample handling and preparation

Handsheet samples and tissue base sheets were conditioned according to TAPPI 402 at 23°C and 50% relative humidity for at least 24 hours prior to testing. Special care was taken to avoid affecting the sheet structure. Areas close to the edge of the sheet were avoided during testing. Curled areas from commercial base sheets were avoided if possible.

Experiment 5. Thickness (Caliper)

Sheet caliper was measured using a Thwing Albert ProGage thickness tester with a 35.7 mm diameter foot at a pressure of 2.0 kPa. This step refers to the TAPPI test method T580 pm-12 (TAPPI TestMethod T580 pm-12) "Thickness of towel, tissue, napkin and facial products (Thickness of towel, tissue, napkin and facial products)". For commercial base sheets, 8-ply stacked paper towels were used to measure samples and a single ply was used for handsheet samples. Six replicates and eight replicates/condition were taken for handsheets and commercial base sheets, respectively, and average values reported. The bulk value (bulk value) was calculated by dividing the average thickness by the average grammage.

Experiment 6. Grammage

The handsheet samples were cut as individual layers with a 112.8 mm diameter circular punch cutter and then weighed on an analytical balance. For commercial base sheets, use a cutter to cut eight layers. Basis weights are calculated based on area and reported in g/ ^m2 /sheet.

Experiment 7. Tensile Strength, Dry

Tensile strength is measured by applying a constant elongation to the sample and recording three tensile fracture properties of paper and board: force per unit width required to break the sample (tensile strength), percent elongation at break (stretch) and the energy absorbed per unit area of the sample before breaking (tensile energy absorption). This method is suitable for all types of paper, but not for corrugated board (corrugated board). This step refers to TAPPI test method T494 (TAPPI TestMethod T494). A minimum of twelve measurements were made for each condition for the handsheet samples and a minimum of 16 measurements were made for the commercial base sheet. The test gap was set at 5 cm (2 inches). The handsheet samples were tested with a single layer and the commercial samples were tested with four layers. A Thwing-Albert QC 3A tensile tester was used.

Experiment 8. Tissue Softness Analyzer (TSA)

Tissue softness was analyzed with the Emtec TSA Tissue Softness Analyzer. TSA measures softness represented by HF (hand feel), TS7 value (related to actual softness), TS750 (related to felt smoothness) and D value (related to hardness). Hand (HF) is a combined parameter and has no units associated with the data values. No HF results were reported for laboratory handsheets because the handsheet samples were not wrinkled. TS7 and TS750 are the peak heights (in dB V2 rms) recorded at 7000 and 750 Hz, respectively. The D value is the distance the tissue is displaced by the impeller during the test when the impeller is pressed against the sample and is expressed in mm/N.

TSA works by holding a tissue sample in a sample loop and measuring acoustic values as the surface of the tissue is brushed by a rotating wheel. Run the handsheet samples using the "Research" algorithm, analyzing the dryer side. HF results were not reported. Commercial base sheet samples use the TPII algorithm. Table 1 below explains the four parameters and how to interpret the data.

Table 1. TSA parameters and data interpretation

parameter Correlation how to explain HF Combination parameters for feel higher = better TS7 Actual softness (from fiber) lower = softer TS750 Felt smoothness/roughness Higher peaks = higher roughness D. hardness lower = harder

Experiment 9. Bulk Viscosity of Emulsion

Viscosity is the resistance of a fluid to deformation by shear or tensile stress. Bulk viscosity (BV) is a measure of a fluid as is. A Brookfield viscometer, DV2T, with a #63 spindle and spindle rotation speed at 30 rpm was used for this study. If the viscosity is higher than 4000cPs, a speed of 20 rpm is used. All viscosities are measured at ambient temperature.

Experiment 10. Particle size analysis

The particle size of the emulsion samples was analyzed with a Horiba Laser Scattering Particle Size Distribution Analyzer, model LA-300. Dilute the samples with deionized water. The RR index is 1.1-0.00i. The median particle size, mean particle size and standard deviation of the distribution are reported in microns (μm).

Experiment 11. Viscosity reduction by hand homogenizer

Use a manual homogenizer to process the emulsion. A certain amount of emulsion (eg 300ml) is added to the cup of a hand homogenizer, and the emulsion is pressed through the small orifice.

Experiment 12. Viscosity reduction by ultrasonic cleaning bath

The emulsion was treated using a conventional ultrasonic cleaning bath (Aquasonic Model 250T, 50/60 Hz Amps: 4). Usually, 400ml of emulsion is filled into a glass bottle, and then placed in an ultrasonic cleaning bath. Connect the ultrasonic cleaning bath and process the emulsion for a certain period of time until the viscosity of the emulsion reaches the target value, ie about 100cPs.

Experiment 13. ORP Measurement of Emulsion

Oxidation-reduction potential (ORP) measurements indicate how a liquid is oxidizing or reducing. In this study, an Oakton ORP tester was used for ORP measurement of emulsions. Place the probe in the emulsion and take the ORP value until the reading stabilizes.

Example

In some of the examples shown below, the commercial softener product FennoSoft 868NV (an imidazoline based softener from Kemira Oyj) was evaluated as a control.

Embodiment 1: the preparation of softener emulsion

Prepare softener concentrates prior to emulsification. Table 2 shows the composition of the formulation.

Table 2. Softener composition before emulsification

A typical laboratory procedure for preparing a 350.0 g softener emulsion with a 30% softener concentrate content according to the present invention is shown below.

1. Add 56.00 g of sorbitan monooleate into a 500 ml stainless steel beaker.

11. Add 28.00 g Polysorbate-20 to the beaker.

III. Add 10.50 g lecithin to the beaker.

IV. Add 5.25g imidazoline to the beaker.

V. Add 5.25g USP Lanolin to the beaker.

VI. Place the beaker on a hot plate with the temperature set at 100°C.

VII. Mix the blend by hand until the lanolin melts and the blend is homogeneous. The temperature should not be lower than 40°C.

VIII. Place the beaker on the platform of the homogenizer IKA T50.

IX. Start the homogenizer at low speed (ie 1000 rpm).

X. Add 245.00 g of warm tap water (~35°C) to the beaker.

XI. Increase speed to 2600 rpm and mix for 1 minute.

XII. Stop the homogenizer and transfer the emulsion to a tank for storage.

The composition of the final emulsion according to the invention with a solids content of 30% is shown below:

1.5wt% lanolin (USP)

3.0wt% non-GMO soy lecithin

1.5wt% imidazoline

16.0wt% sorbitan monooleate

8.0 wt% polysorbate-20 (polyethylene glycol sorbitan monolaurate)

70.0wt% water

Imidazolines are produced by reaction of fatty acids with diethylenetriamine, and then cyclized and finally quaternized by diethyl sulfate. The fatty acid is preferably oleic acid or palmitic acid. The ratio of oleic acid to DETA is preferably in the range of 1-2. The cyclization reaction is preferably completed to an extent of 80% to 95%, and the quaternization reaction is preferably completed to an extent of 90% to 95%.

Example 2: Dry Sheet Spray

The results of dry sheet spraying are shown in Figures 2-6. 868NV refers to a 20% solids emulsion of the commercial control FennoSoft 868NV. 695-71A is a softener emulsion according to the invention having a 30 wt-% softener concentrate content. In Figure 2, the dry tensile (DT) of both emulsions decreased by almost 30%. The HF values of the two emulsions shown in Figure 3 increased by 8%. TS7 (Figure 4) and TS750 (Figure 5) were reduced for both emulsions. Spraying through the dry sheet increased the D value (Figure 6). No significant differences in TSA test results were observed between 695-71A and 868NV.

Table 3. Emollient composition and dosage of Example 2.

Table 4. Softness measurements for Example 2.

softener HF TS7,dB TS 750,dB D,mm/N DT, gf/3in 695-71A 91.7 11.520 11.157 3.89 177 868NV 91.3 11.731 11.540 3.94 173 blank-air 84.5 15.343 13.113 3.67 250

Example 3: Wet Web Spray

Two blank conditions were present in the wet web study, including 50:50 eucalyptus:softwood (SW) and 70:30 eucalyptus:SW. Due to the higher eucalyptus content, 70:30 eucalyptus offers better softness than 50:50 eucalyptus. Wet web sprays of the softeners tested were applied only to the 50:50 eucalyptus-cork blend. The purpose of using 70:30 eucalyptus:SW as a target was to assess whether softener treatment could provide 20% fiber replacement of eucalyptus. Figure 7 shows the dry stretching results. A softener dose response to dry stretching can be observed for softener emulsion 695-71A according to the invention. In addition, the bulk density of 695-71A was significantly higher than that of the 50:50 Eucalyptus:SW blank (shown in Figure 8). TSA results are shown in Figures 9 and 10. The TS7 of 695-71A decreased and the D value increased. At a dosage of 6 kg/t dry stock (12 lb/ton dry stock) based on weight of softener concentrate, 695-71A produced slightly better softness results than the 70:30 eucalyptus:SW blend.

Table 5. Dosage, Dry Stretch, Loft and Softness Values for Example 3.

Example 4: Wet end application

The strength and softness results are shown in Figures 11-15 for wet end application of softener. In these figures, blank 1 is a 50:50 eucalyptus-softwood fiber blend, and blank 2 is a 70:30 eucalyptus-softwood fiber blend. The two blanks did not use any chemical additions. All chemical treatments are only used on the 50:50 eucalyptus-cork blend. The softness target is blank 2. Blank 2 provided better softness than Blank 1 due to the higher eucalyptus content. The purpose of using Blank 2 as the target was to assess whether the softener treatment could provide a 20% replacement of eucalyptus fiber.

When used alone, softener emulsion 695-71A according to the present invention did not reduce dry stretch (FIG. 11). This is reasonable since most of the components in this formulation are non-ionic. 695-71A shows a dosage (by weight of softener concentrate) at 6 kg/t dry stock (12 lb/t dry stock) when it is used with the commercial coagulant FennoFix 501 (Kemira Oyj) count) lower dry stretch. With regard to bulking performance (Figure 12), the results were not very consistent. 695-71A at a dosage of 6kg/t dry pulp (12lb/ton dry pulp) (by weight of softener concentrate), together with dosage at 3kg/t dry pulp (6lb/ton dry pulp) (by weight of solids Density meter) FennoFix 501 resulted in only an increase in bulk. This condition produced higher loft values than Blank 2 (ie, 70:30 eucalyptus-cork). Figures 13 to 15 show the TSA results. 695-71A does not lower TS7 when no coagulant is used. 695-71A at 6kg/t dry (12lb/t dry) dosage (by weight of softener concentrate) showed a slight decrease in TS7 and an increase in D value when FennoFix 501 was used. FennoFix 501 may help keep the softener on the fiber, which leads to an increase in the D value (another indication of better softness).

Table 6. Dosage, Dry Stretch, Loft and Softness Values for Example 4.

Example 5. Viscosity reduction by hand homogenizer

An emulsion having a softener concentrate content of 30% was prepared according to the procedure shown in Example 1. The softener emulsion was processed through multiple passes through a high shear homogenizer until a viscosity of about 100 cPs was reached. Table 7 shows the change in viscosity after treatment with a hand homogenizer. It can be clearly seen that high shear force can significantly reduce the viscosity. The results of particle size analysis are shown in Table 8. The particle size also decreased after treatment. In addition, the treated emulsion exhibited a lower particle size standard deviation, indicating a narrower particle size distribution.

Table 7. Viscosity reduction of softener emulsions processed by hand homogenizer.

Number of passes processed through a manual homogenizer Viscosity of 695-71A, cPs as it is 3288 first pass 896 second pass 316 third pass 200 fourth pass 112

Table 8. Particle size analysis of emulsions of the invention processed by a manual homogenizer.

695-71A, AS IS 695-71A, 4 passes Particle size - median, μm 1.714 0.987 Particle size-average value, μm 2.813 1.212 Particle size - standard deviation, μm 3.293 0.781

The phenomenon of cavitation during homogenization involves the release of entrained air. In these softener emulsions, no oxidizing or reducing agents are present. Therefore, the ORP value of the emulsion is only contributed by entrained or dissolved oxygen in the air. This suggests that the ORP value of the emulsion can indicate the effectiveness of removing entrapped air by a manual homogenizer. Table 9 shows the results of the ORP values and corresponding viscosities of 695-71A during processing through a hand homogenizer. These results show that both the ORP value and the viscosity decrease after work-up through the homogenizer.

Table 9. Viscosity and ORP results after processing softener emulsions through a hand homogenizer.

Example 6. Viscosity reduction by sonication

During sonication, air bubbles were observed on the surface of the softener emulsion. Figure 16 shows the change in emulsion viscosity during sonication. The initial viscosity is higher than 3000cPs. As the processing time increases, the viscosity of the emulsion decreases. After 26 minutes, the viscosity reached 136 cPs. Table 10 shows the results of particle size analysis. Sonication produced smaller mean and median particle size values compared to untreated emulsions.

Table 10. Particle size analysis of softener emulsions by sonication.

695-71A, AS IS 695-71A, 26min Particle size - median, μm 1.714 1.530 Particle size-average value, μm 2.813 2.553 Particle size - standard deviation, μm 3.293 3.541

.

Claims (15)

1. A softener concentrate for use in the manufacture of paper, tissue or board, said softener concentrate comprising: - 5% to 10% by weight of the total weight of the softener concentrate of imidazoline-based surfactants having a carbon chain longer than 10 carbon atoms; - softeners based on lanolin; - phospholipids; and - Surfactant blends comprising polysorbates, sorbitan ester based surfactants, polypropylene glycol, polyethylene glycol and their esters, silicon based softeners or any combination thereof. 2. The softener concentrate according to claim 1, wherein said concentrate comprises 5 to 10 wt% of lanolin-based softener, 5 to 20 wt% of the total weight of said softener concentrate. Phospholipids and 60 wt% to 85 wt% surfactant blend. 3. A softener concentrate according to claim 1 or 2, wherein the concentrate comprises 5 wt% imidazoline-based surfactant, 5 wt% lanolin-based surfactant, based on the total weight of the softener concentrate Softener, 10wt% phospholipid and 80wt% surfactant blend. 4. A softener concentrate according to any one of the preceding claims, wherein the imidazoline-based surfactant comprises a carbon chain of 16 to 18 carbon atoms. 5. A softener concentrate according to any one of the preceding claims, wherein the lanolin-based softener comprises USP grade lanolin. 6. The softener concentrate according to any one of the preceding claims, wherein the phospholipid comprises lecithin, preferably lecithin derived from soybean, sunflower, rapeseed and/or cottonseed. 7. A softener emulsion for use in the manufacture of paper, tissue or cardboard, said softener emulsion comprising: - 20 to 50 wt%, preferably 25 to 30 wt%, of the softener concentrate according to any one of the preceding claims 1 to 6, based on the total weight of the softener emulsion, and - 50% to 80% by weight, preferably 70% to 75% by weight of water, based on the total weight of the softener emulsion. 8. The softener emulsion of claim 7, wherein the softener emulsion further comprises an electrolyte selected from the group consisting of soluble salts, acids, bases, polyelectrolytes, or any combination thereof. 9. The softener emulsion according to claim 7 or 8, wherein the softener emulsion comprises 0.01 to 1.0 wt%, preferably 0.01 to 0.5 wt%, more preferably 0.01 to 0.3 wt%, based on the weight of the softener emulsion or an electrolyte in an amount of 0.01 to 0.25 wt % and even more preferably 0.01 to 0.05 wt %, and wherein the softener emulsion has a Brookfield viscometer, DV2T, measured at room temperature with a #63 spindle and a spindle speed of 30 rpm A viscosity below 500 cPs, preferably below 200 cPs, more preferably below 100 cPs, even more preferably below 50 cPs. 10. A method for producing an emulsion of softener, said method comprising: - providing a softener concentrate according to any one of the preceding claims 1 to 6, - emulsifying said softener concentrate with water, thereby forming a softener emulsion comprising from 20% to 50% by weight of the softener concentrate relative to the total weight of said softener emulsion, - Treating the softener emulsion with a high shear homogenizer and/or ultrasonic energy to reduce the viscosity of the softener emulsion. 11. The method of claim 10, wherein the method further comprises adding an electrolyte selected from the group consisting of soluble salts, acids, bases, polyelectrolytes, or any combination thereof. 12. The method according to claim 10 or 11, wherein, at 0.01 wt% to 1.0 wt%, preferably 0.01 wt% to 0.5 wt%, and more preferably 0.01 wt% to 0.05 wt% of the weight of the softener emulsion % of the amount of electrolyte added. 13. The method according to claim 11 or 12, wherein the electrolyte is added before, during and/or after the emulsification step, preferably after the emulsification step, and/or between the high shear homogenizer and and/or adding said electrolyte before, during and/or after sonication. 14. The method according to any one of the preceding claims 10-13, wherein the softener emulsion is treated with ultrasonic energy for a period of 1 to 60 minutes, preferably 10 to 30 minutes. 15. A process for the manufacture of paper, tissue or board wherein a softener emulsion is added to a fiber stock having a consistency of 0.05 wt% to 8 wt% at the wet end of a paper machine; and/or applying the softener emulsion to a wet web having a moisture level of 30% to 90% by weight of water in the wet web; and/or applying the softener emulsion to dry paper On the sheet or converted paper roll, the dried paper sheet or converted paper roll has a moisture level of less than 12% based on the weight percent of water in the dried sheet or converted roll.