KR20090018117A - Use of polyvinylamine to improve oil and water sizing in cellulosic products - Google Patents

Abstract

The presence of both a water sizing agent and an oil sizing agent in a paper making furnish is detrimental in that each has an adverse effect on the sizing property of the other. It has now been found that this adverse effect can be counteracted or lessened by the presence in the furnish of a polyvinylamine.

Description

USE OF POLYVINYLAMINE TO IMPROVE OIL AND WATER SIZING IN CELLULOSIC PRODUCTS}

The present invention is directed to improving oil / oil and water sizing of cellulosic materials, in particular paper products, by using polyvinylamine in combination with oil sizing agents and water sizing agents.

Sizing agents are used in the papermaking process to prevent water or fats, ie oils from adhering or penetrating the paper to weaken and / or contaminate the paper. Sizing agents can be classified as reactive or non-reactive. They can also be classified as internal or surface sizing agents. Reactive sizing agents are commonly used for internal sizing in combination with paper fibers.

The sizing agent may be added to the paper finished material before it is introduced into the wetting stage of the papermaking machine. Alternatively, the same sizing agent may be sprayed or nipped onto the newly formed paper as the paper passes. If a sizing agent is added to the pulp slurry (ie finished stock) it will not adhere to the pulp or remain on paper. This can be achieved by using charged formulations as opposed to pulp. Paper sizing agents prevent water or oils from penetrating the paper excessively. They are used where water resistance or oil resistance is required in the paper end use. There is no sizing agent that has enough of these two resistances. The most efficient oil sizing agents for cellulosic materials such as paper contain long chain linear fluorinated carbons. In general, carbon fluorides have a low surface energy and are not easily wetted by oil based materials. In contrast, formulations containing non-fluorinated hydrocarbon chains are good water sizing agents.

However, when a combination of an oil-resistant fluorinated carbon-based formulation and a water-resistant hydrocarbon-based compound is used together in the papermaking process, each has a detrimental effect on each other's performance. Therefore, more materials or compounds must be used to compensate for the disadvantageous loss of resistance.

As described in US Pat. No. 5,252,754 to Bottorff, long chain fluorinated carbons are efficient oil sizing agents for cellulosic materials such as paper because of their low surface energy. However, such fluorinated carbon based sizing agents are generally inefficient in water resistance, especially when they contain hydrophilic bases. On the other hand, hydrocarbon based sizing compounds such as alkyl ketene dimers (AKDs) are effective water sizing agents but are inefficient for oil sizing purposes. When a combination of hydrocarbon based materials and fluorocarbon based materials is used, they adversely affect the performance of each other in the paper. This detrimental relationship generally results in an inefficient treatment, since the amount of compound must be increased to achieve both sufficient oil and water resistance in the paper.

It has been surprisingly found that due to the presence of polyvinylamine in paper or cardboard finishes containing both oil (or oil) sizing agents and water sizing agents, the harmful action is counteracted.

Summary of the Invention

In one aspect, the present invention relates to a papermaking method or a paperboard manufacturing method, wherein the finished paper contains both an oil sizing agent and a water sizing agent, and further contains a polyvinylamine.

Another aspect of the invention is the order in which these agents are added to the finish. Water sizing agent is added to the paper finish. At this time, polyvinylamine is added to the paper finish before or after the addition of the water sizing agent, and then the oil sizing agent is added.

The present invention also provides a paper finish containing at least one polyvinylamine, water sizing agent and oil sizing agent.

<Detailed Description of the Invention>

An important aspect of the present invention is the addition of a water soluble cationic polyvinylamine when both oil and water sizing agents are used in the papermaking process.

The finished stock (ie pulp) is passed through a paper machine which consists of a head box, sheet forming zone and drying zone sequentially.

Polyvinylamines useful in the present invention include, without limitation, those produced through free radical solution polymerization of n-vinylformamide. The resulting nonionic polyvinylformamide can be base hydrolyzed to produce primary amine cationic functional groups and sodium formate on the polymer as byproducts. Compounds effective for this purpose include vinylamine polymers having a molecular weight ranging from 300,000-400,000 via size exclusion chromatography (SEC) and reacted at hydrolysis levels of 35-100%, preferably 50-100%, It is not limited to this. Copolymers of polyvinylamine can be used. Comonomers include vinyl acetate or vinyl propionate monomers.

The polyvinylamine polymer can be incorporated into the water suspension of the fibers used to form the web, ie the finish.

Furnish means a mixture of various materials blended into a stock suspension from which paper or paperboard is made, mainly consisting of fibrous materials (pulps), sizing or strength materials, or other additives such as fillers and dyes do.

Pulp means a fibrous material made from wood, cotton, grass, or the like through chemical or mechanical methods used to make paper, cardboard, or cellulose products.

By wire is meant a woven material of plastic or metal for use in forming a web of paper or paperboard from lean pulp slurry.

Headbox means a flow control chamber that receives lean paper stock or finished stock from the stock manufacturing system and acts to spread the flow evenly over the entire width of the forming wire.

Sheet formation refers to the process by which lean fiber finishes are formed into a wet web through vacuum and gravity drainage.

By drying zone is meant some of the methods of papermaking including removing excess water from the wet web of paper or cardboard through direct contact with a heated drying cylinder.

By web is meant a sheet of paper or cardboard of full width derived from a paper machine.

Suitable water sizing agents include alkyl ketene dimers (AKD) or alkenyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), rosin based sizing agents such as rosin soaps, dispersed rosin and the like.

Suitable oil sizing agents include fluorocarbon-containing polymers such as those that fluorinated alkyl groups.

In a preferred process aspect of the invention, oil sizing agents and water sizing agents can be added to the finish in an amount of from 0.005% to 1% active treated solids based on the total finish solids, wherein polyvinylamine is the total finish solid Based on 0.001% to 1% active treated solids.

Example A, below, shows a typical detrimental relationship between oil sizing agents and water sizing agents in cellulose based systems that require large amounts of water and oil sizing agents.

Example A

To produce paper handsheets, 20 cm × 20 cm handsheets with a substrate weight of 160 g / m ² were prepared using the Noble and Wood Labs molder.

Finished feeds containing bleached soft kraft pulp and bleached chemical thermomechanical pulp, which required significant water sizing and oil sizing, were obtained from commercial manufacturers. The pulp was blended at a 1: 1 ratio and refined in a laboratory cycle shaker at 470 ml Canadian Standard Free Water (CSF). As outlined in Table A, commercial water sizing agents and oil sizing agents were sequentially added to an aliquot of the pulp. Stocks were shaken using an overhead mixer assembly set at 1,400 rpm. 30 seconds after the addition of the water sizing agent, an oil sizing agent was added to the pulp. After the addition of the oil sizing agent, the mixture was further mixed for 30 seconds to start the hand sheet preparation. Handsheets were formed on a 100 mesh screen and passed through a felt roll press set to 35 psi (single pass) and dried to 3-4% moisture using a drum dryer.

To determine the water and oil resistance of the finished paper, the performance was tested through the Hot Water Cobb test and the Hot Oil Cobb test. These test procedures are as follows. The hot water cove test cuts a paper sample to 12.5 cm x 12.5 cm, weighed to almost 0.01 g and then fixed in a 100 ml Cove Ring instrument. A 50 ml water sample at 180 ° F. is then poured onto the cove ring and top of the paper. Exactly two minutes after contact with the paper sample, water is poured quickly from the rings. The wet paper sample is removed from the instrument and placed between the two blotter papers (wet side up). The cove hand roller is moved back and forth once on the sample without additional force to remove excess water from the paper sample. Immediately thereafter the weight of the wet paper sample is weighed back to almost 0.01 g. Calculate the weight g / m ² of water absorbed by subtracting the adjusted sample weight from its final weight and multiply by 100.

The hot oil cove test is the same as the hot water cove test except that the oil (Wesson® Corn Oil) is used at 220 ° F. instead of water. The only other difference in the oil test is that rather than using a cove hand roller to remove excess oil, the wet paper sample is hand crimped between the blotters and then gently wiped the sample with a clean Kimswipes® towel. Is that. The hot oil cove test calculates the weight g / m ² of absorbed hot oil using the same calculation described under Hot Water Cove Test.

In both the hot water cove test and the hot oil cove test, high test results indicate high absorption through paper samples. Conversely, low cove test values indicate low surface wetting and permeability and good sizing. The data in Table A shows the typical negative impact of water sizing agents on the performance of oil sizing materials. For example, as the throughput to the water sizing agent increases, the water sizing improves, but the oil sizing decreases. The water sizing agent included an alkyl ketene dimer and the oil sizing agent was a perfluoroalkyl containing compound.

TABLE A

The following definitions apply to Table A.

Commercially available AKD water sizing agents: Hercon® 79-Hercules Incorporated

Commercial oil sizing agents: impress® FP-100-Hercules Incorporated

% By weight: Addition% of active treated solids based on total finished solids

The following examples show the surprising beneficial effects of polyvinylamine on both water and oil resistance in cellulose based systems requiring large amounts of water and oil sizing agents.

Example 1

The data from Example 1 is summarized in Table 1. The study described in Example A except that the finish contained 60% southern bleached softwood kraft and 40% northern bleached hardwood kraft commercial pulp refined to 480 ml Canadian Standard Yeosu (CSF). Handsheets were prepared using the same papermaking method as one. The target substrate weight was 248 g / m ² . The order of addition of the chemicals was the same as described in Example A, except that when polyvinylamine was included in the test, it was added to the blended finish 30 seconds before the addition of the water sizing agent. The performance of the handsheets was tested in the same manner as described in Example A except that the 2% Ambient Saline Cobb test was performed instead of the hot water cove test. The brine used in this test is at room temperature and is derived from deionized water treated with 2% by weight of NaCl. Except for these differences, the test procedure was the same as the hot water cove test described in Example A.

The data summarized in Table 1 shows the positive action of polyvinylamine on both the water sizing test results and the oil sizing test results. Low saline cove test values and low hot water cove test values indicate that the addition of polyvinylamine has achieved an effective balance of water resistance and oil resistance. The water sizing agent included an alkyl ketene dimer and the oil sizing agent was a perfluoroalkyl containing compound. Polyvinylamine was a solution polymer reacted at a hydrolysis level of 50%.

The following definitions apply to Table 1.

Commercial polyvinylamines: Hercules® PPD M-1189-Hercules Incorporated

Commercially available AKD water sizing agents: Hercon® 80-Hercules Incorporated

Commercial oil sizing agents: Impress® FP-100-Hercules Incorporated

% By weight: Addition% of active treated solids based on total finished solids

Example 2

Data from Example 2 are summarized in Table 2. In this study, 160 g / m ² handsheets were prepared using the same papermaking method and finish blend as described in Example A. For pulp refining, the target Canadian standard looseness was 470 ml. The order of addition of the chemicals is described in Example A, except that when an anionic polymer is included in the test, it is added to the mixed finish 30 seconds after the addition of the water sizing agent and 30 seconds before the addition of the oil sizing agent. Same as one. If polyvinylamine was included in the test, it was added to the mixed finish 30 seconds before the addition of the water sizing agent. The performance of the handsheets was tested in the same manner as described in Example A.

The data in Table 2 also shows the beneficial effect of polyvinylamine on both water sizing and oil sizing as low cove values are achieved due to the addition of polyvinylamine to the test finish. Water sizing agents included alkyl ketene dimers. The oil sizing agent was a perfluoroalkyl containing compound and the polyvinylamine was a solution polymer reacted at a hydrolysis level of 50%. The anionic polymer was a solution copolymer of acrylamide and acrylic acid (Hercobond 2000). Anionic polymers have been used as retention agents to help improve fine solid retention in the web during the sheet formation process.

The following definitions apply to Table 2.

Commercial polyvinylamines: Hercules® PPD M-1189-Hercules Incorporated

Commercially available water sizing agents (1): 60:40 Blend ReTen® 204LS / Hercon® 70-Hercules Incorporated

Commercially available water sizing agents (2): Hercon® 70-Hercules Incorporated

Commercial Anionic Polymers: Hercobond® 2000-Hercules Incorporated

Commercial oil sizing agents: Impress® FP-100-Hercules Incorporated

% By weight: Addition% of active treated solids based on total finished solids

Example 3

Data from Example 3 is summarized in Table 3. The same paper as described in Example A except that the finish contained 70% southern bleached softwood kraft and 30% northern bleached hardwood kraft commercial pulp refined to 405 ml Canadian standard Yeosu. The handsheets were prepared using the method. The target substrate weight was 149 g / m ² . The order of addition of the chemicals is the same as described in Example A, except that when the test includes polyvinylamine or branched polyamine, it is added to the blended finish 30 seconds before the addition of the water sizing agent. It was. In addition, the anionic polymer and colloidal silica were added sequentially 30 seconds after the addition of the water sizing agent and 30 seconds before the addition of the oil sizing agent (with a mixing time of 30 seconds before the addition of each substance). The performance of the handsheets was tested in the same manner as described in Example A.

The data in Table 3 summarizes the positive action of polyvinylamine on water and oil sizing results. The trend associated with polyvinylamine also shows that it is possible to reduce the addition amount of water sizing agent and oil sizing agent, in which the cove test value is effectively kept low indicating high water resistance and oil resistance. Test data relating to branched polyamines indicate difficulty in achieving the same effective balance in water sizing and oil sizing compared to test conditions comprising polyvinylamine.

In this example, the branched polyamine was a solution polymer with quaternary amine functionality. Polyvinylamine was a solution polymer that was reacted at 50% hydrolysis level with predominantly linear structure and primary amine functionality. The water sizing agent included an alkyl ketene dimer and the oil sizing agent was a perfluoroalkyl containing compound. The anionic polymer was an emulsion copolymer of acrylamide and acrylic acid. The silica component was an aqueous dispersion of colloidal silica particles. Anionic polymers and colloidal silicas were added to the finish to help increase the fine solid retention in the web during the formation process.

The following definitions apply to Table 3.

Commercially branched polyamines: Nalco 7607-Nalco

Commercial polyvinylamines: Hercules® PPD M-1189-Hercules Incorporated

Commercially available water sizing agents: Hercon® 79-Hercules Incorporated

Commercial Anionic Polymers: PerForm® PA8137-Hercules Incorporated

Commercial Colloidal Silicas: Positek 8691-Nalco

Commercial oil sizing agents: Impress® FP-100-Hercules Incorporated

% By weight: Addition% of active treated solids based on total finished solids

Claims (8)

A papermaking method comprising using a finished paper containing both an oil sizing agent and a water sizing agent as a part of the finished paper, and also containing polyvinylamine. The process of claim 1 wherein the oil sizing agent is present in the finish in an amount of 0.005% to 1% active treated solids based on the total finish solids and the water sizing agent is 0.005% to 1% based on the total finish solids Wherein the polyvinylamine is present in an amount of 0.001% to 1% active treated solids based on the total finish solids. The papermaking method of claim 1 wherein the oil sizing agent is a fluorocarbon containing polymer and the water sizing agent is an alkyl ketene dimer. 3. The papermaking process of claim 2 wherein the oil sizing agent is a fluorocarbon containing polymer and the water sizing agent is an alkyl ketene dimer. 3. The papermaking process of claim 2 wherein the hydrolysis level of the polyvinylamine is at least 35%. The method of claim 1, wherein the order of adding the oil sizing agent, the water sizing agent, and the polyvinylamine to the finished material includes adding the water sizing agent, and then adding the polyvinylamine before or after the addition of the water sizing agent, The papermaking method then adds an oil sizing agent. The method of claim 3, wherein the order of adding the fluorocarbon-containing polymer, the alkyl ketene dimer and the polyvinylamine is added to the alkyl ketene dimer, wherein the polyvinylamine is added before or after the addition of the alkyl ketene dimer. And then a fluorocarbon containing polymer. Paper finished paper containing oil sizing agent, water sizing agent and polyvinylamine.