Patent Application
20240254362
The present invention relates to a method of making an acid neutralizing polymer, and more particularly to a method of making an acid neutralizing polymer with further modification of the polymer through reaction with a basic salt.
Polyamides, including nylon 6, nylon 6,6 (nylon 66) and nylon 12, are synthetic polymers amenable to functionalization through chemical modification of the amide groups within the polymer backbone. By way of example, nylon fabrics have been modified to increase their tensile strength for military application or modified to improve dye acceptance.
In U.S. Pat. No. 11,078,331 (“the ‘331 Patent”) and U.S. Patent Publication No. 2021/0324140 (“the ‘140 Publication”), the entirety of each being incorporated by reference herein, a process is described to create an acid neutralizing powder through a reaction in dimethyl formamide (DMF). This wet chemistry process has the disadvantage of providing only a low yield and hence the reacted product is limited in the extent to which it can provide the required acid neutralization properties. Additionally, the process by-products (butanol from the reaction and DMF vapor from the drying step) may be difficult to handle from an environmental perspective.
U.S. Patent Publication No. 2022/0289910 (“the ‘910 Application”), the entirety of which is incorporated by reference herein, discloses an alternative process for producing acid neutralizing poly materials through reactive extrusion. While overcoming many of the drawbacks associated with the wet chemistry synthesis, the reactive extrusion system and method described within the ‘910 Publication may be improved upon, such as simplifying the reaction and eliminating potentially harmful or caustic reagents.
Thus, what is needed is an acid neutralizing polymer having a high amide modification which is further modified by reaction with a basic salt to produce a polymer material with increased acid neutralization capacity. The present invention addresses these, as well as other, needs.
As described in the ‘331 Patent, and the ‘140 and ‘910 Publications, the Acid Neutralizing Polymer Reaction (ANPR) is a method of creating an acid neutralizing polymer that can be used, for instance and without limitation, to generate both powder and resin in order to serve the Acid Proof Coatings & Lining market and the Personal Protection Equipment (PPE) market. By way of example, these powders may be added to floor coatings and also made into floor mats to protect equipment and personnel by neutralizing acids on contact.
Products manufactured with this technology exceed the performance of corrosion resistant materials such as PVC, PTFE, phenolic epoxy, and rubber floor mats through a combination of acidic corrosion resistance and acid neutralization. In addition, these polymers can be used to neutralize acids multiple times by refreshing them via a proprietary reactivation solution.
Beyond traditional wet chemistry, compounding technology may be used for reacting an amino nylon polymer with additional chemicals within a polymer compounding process such as via a twin-screw extruder, internal mixer, continuous mixer or a reciprocating single screw compounding machine. The compounding reaction involves the melt mixing of the ingredients using an optimized set of process conditions which provide the necessary temperature of reaction, residence time, and degree of shear induced dispersion.
An advantage of the reactive compounding process is that it is possible to generate a much higher yield of the reacted final product. During the reactive compounding process, the reactions take place when the polymer is in the molten state and is undergoing intensive dynamic shear. This allows for intimate mixing of the reactants and optimal reaction yield by controlling temperature (which affects reaction rate) and residence time (which affects the extent of reaction).
By way of example and as set forth more fully in the ‘331 Patent, and/or the ‘140 and ‘910 Publications, reactive compounding can be accomplished in three steps. In the first step, amino nylon is blended with a halogenated-dimethylalkylamine such as 2-chloro-N,N-dimethylethylamine hydrochloride, an acid neutralizing compound such as calcium carbonate, and a heat stabilizer suitable for nylon, such as BRUGGOLEN H10 available from L. Brüggemann GmbH & Co. KG, Heilbronn, Germany. The first step of the reaction neutralizes the 2-chloro-N,N-dimethylethylamine hydrochloride. The second step involves reacting additional amino nylon with calcium hydroxide and a heat stabilizer suitable for nylon. The heat stabilizer may be the same or different than the heat stabilizer using in the first step. The second step generates anionic nitrogen atoms for reaction in the third step. The third step involves the combination of the reaction products generated in the first and second steps to produce the final product. Depending on the particular melt compounding process used, the final product can be produced in multiple steps or in either 2 or 1 steps.
As further described in the ‘331 Patent, and/or the ‘140 and ‘910 Publications, a method of making an acid neutralizing polymer material includes preparing a first reaction mixture comprising a buffering agent and an amine salt of either a halogenated tertiary amine or a haloalkyl heterocyclic aromatic amine. The first reaction mixture is added to a first compounding machine and reacted for a time and at a temperature sufficient to produce a neutralized amine. A second reaction mixture including a polyamide material and a strong base is prepared, added to the first reaction product and reacted for a time and at a temperature sufficient to produce the acid neutralizing polymer material. Alternatively, the buffering agent, amine salt of either a halogenated tertiary amine or a haloalkyl heterocyclic aromatic amine, and the polyamide material may be added and reacted for a time and at a temperature sufficient to produce the acid neutralizing polymer material.
The accompanying drawings form a part of this specification and are to be read in conjunction therewith, wherein like reference numerals are employed to indicate like parts in the various views, and wherein:
Polyamides, such as but not limited to nylon 6, nylon 66 and nylon 12 may be modified through base-induced removal of the amido hydrogen to generate a reactive nitrogen atom within the polyamide backbone. As described more fully in the ‘331 Patent, and the ‘140 and ‘910 Publications, the nitrogen reacts with a basic compound, such as an amine, to covalently bond a basic pendant group to the polyamide chain. This basic pendant group may then provide a reaction site for further chemical processes, such as neutralizing hydrogen ions (acid) which come into contact with the modified nylon. Alternatively, as will be discussed in greater detail below, the basic pendant group may further react with a basic salt to further modify the nylon surface to increase acid neutralizing reactivity of the material.
As generally disclosed within the ‘331 Patent, and the ‘140 and ‘910 Publications, an acid neutralizing polymer end product may be produced through traditional wet chemistry approaches or through reactive extrusion processes. By way of example, virgin polyamide material may be reacted with a solid, strongly basic material (e.g., a basic salt of a strong base). The virgin polyamide material may become activated by removal of an amide hydrogen on the polyamide polymer backbone. Without limitation thereto, the activated polyamide material may then be reacted with a halogenated-dimethylalkylamine having a general chemical formula of (CH3)2N-R-X where R may be an alkyl containing 1-12 carbon atoms and X is either chlorine or bromine. In one particular aspect, the halogenated-dimethylalkylamine is 2-chloro-N,N-dimethylethylamine.
The activated polyamide material and halogenated-dimethylalkylamine are then reacted whereby the activated polyamide material becomes functionalized by the dimethylalkylamine to produce an acid neutralizing polyamide. Additional or alternative process steps and reagents, such as but not limited to an acid neutralizing compound such as calcium carbonate and a heat stabilizing agent, such as but not limited to BRUGGOLEN H10 available from L. Brüggemann GmbH & Co. KG, Heilbronn, Germany, may be included, as necessary, to produce the desired final acid neutralizing polyamide material product.
Additional acid neutralizing polymer materials may be prepared through the use of alternative amine starting reagents. In one specific example, one alternative amine may be a haloalkyl heterocyclic aromatic amine such as 4-(Chloromethyl)pyridine hydrochloride. 4-(Chloromethyl)pyridine hydrochloride may be a suitable reactant because its chain length is similar to that of many nylon monomers, such as nylon 6, nylon 6,6 or nylon 12. Additional alternative amine compounds may include halogenated tertiary amines, such as and without limitation thereto, 4-(Dimethylamino)benzoyl chloride hydrochloride, 2-Dimethylaminoisopropyl chloride hydrochloride, 2-(Diethylamino)ethyl chloride hydrochloride and 6-Chloro-N,N-dipropylhexan-1-amine.
As described, the acid neutralizing polymer material can be made into fabric or mesh or can also be pelletized to be mixed with other polymers. The pellets can also be further ground into powder to be used as an additive in coatings and other building materials such as mortar and polymer concrete in order to impart acid neutralization functionality.
From the above, it should be noted that each of the reactions may take place at any desired temperature, but preferably below the boiling point of the respective materials. Additionally, each reaction may also occur at any desired pressure within the compounding machine. Reaction times will thus depend upon the flow rate of the compounding machine, and the temperature and pressure of each reaction within the compounding machine.
In accordance with an aspect of the present invention, each of the embodiments of an acid neutralizing polymer material produced in accordance with the disclosures of the ‘331 Patent, and the ‘140 and ‘910 Publications may be further modified with a basic salt solution to increase the neutralization efficiency of the polymer material. Turning now to
At step 114, the acid neutralizing polymer material layer 210 is coated with a solution 212 (
With reference to
The following are representative and non-limiting examples of a modified polymer material evidencing the manufacture and use of a modified acid neutralizing polymer material in accordance with the present invention:
Results—Experiment 1 showed a pH increase from pH 0.3 to pH 0.5. This pH increase is believed to be due to the innate acid neutralizing ability of the ANPM.
Results—Experiment 2 showed that the pH increase from pH 0.3 to pH 6.0. Experiment 2 was repeated ten times where it repeatedly performed this action.
Results—Experiment 3 showed a pH increase from pH 0.3 to pH 6.3. Experiment 3 was repeated ten times where it repeatedly performed this action.
Results—Experiment 4 showed a pH increase from pH 0.3 to pH 8.2. Experiment 4 was repeated ten times where it repeatedly performed this action.
Results—Experiment 5 showed a pH increase from pH 0.3 to pH 6.0. Experiment 5 was repeated ten times where it repeatedly performed this action.
Although the invention has been described with reference to preferred embodiments thereof, it is understood that various modifications may be made thereto without departing from the full spirit and scope of the invention as defined by the claims which follow.
This application claims the benefit of U.S. patent application Ser. No. 63/482,666, filed on Feb. 1, 2023 and entitled POLYMER MATERIALS FUNCTIONALIZED WITH BASIC SALTS, the contents of which are hereby incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63482666 | Feb 2023 | US |
